Friday, October 12, 2007

Types of Fish Diseases

There are two broad categories of disease that affect fish, infectious and non-infectious diseases. Infectious diseases are caused by pathogenic organisms present in the environment or carried by other fish. They are contagious diseases, and some type of treatment may be necessary to control the disease outbreak. In contrast, non-infectious diseases are caused by environmental problems, nutritional deficiencies, or genetic anomalies; they are not contagious and usually cannot be cured by medications.
Infectious diseases. Infectious diseases are broadly categorized as parasitic, bacterial, viral, or fungal diseases.

Parasitic diseases of fish are most frequently caused by small microscopic organisms called protozoa which live in the aquatic environment. There are a variety of protozoans which infest the gills and skin of fish causing irritation, weight loss, and eventually death. Most protozoan infections are relatively easy to control using standard fishery chemicals such as copper sulfate, formalin, or potassium permanganate. Information on specific diseases and proper use of fishery chemicals is available from your aquaculture extension specialist.

Bacterial diseases are often internal infections and require treatment with medicated feeds containing antibiotics which are approved for use in fish by the Food and Drug Administration. Typically fish infected with a bacterial disease will have hemorrhagic spots or ulcers along the body wall and around the eyes and mouth. They may also have an enlarged, fluid-filled abdomen, and protruding eyes. Bacterial diseases can also be external, resulting in erosion of skin and ulceration. Columnaris is an example of an external bacterial infection which may be caused by rough handling.

Viral diseases are impossible to distinguish from bacterial diseases without special laboratory tests. They are difficult to diagnose and there are no specific medications available to cure viral infections of fish. The most important viral infection which affects fish production in the southeastern United States is Channel Catfish Virus Disease, caused by a herpes virus. Consultation with an aquaculture or fish health specialist is recommended if you suspect a bacterial or viral disease is killing your fish.

Fungal diseases are the fourth type of infectious disease. Fungal spores are common in the aquatic environment, but do not usually cause disease in healthy fish. When fish are infected with an external parasite, bacterial infection, or injured by handling, the fungi can colonize damaged tissue on the exterior of the fish. These areas appear to have a cottony growth or may appear as brown matted areas when the fish are removed from the water. Formalin or potassium permanganate are effective against most fungal infections. Since fungi are usually a secondary problem it is important to diagnose the original problem and correct it as well.

Non-infectious diseases. Non-infectious diseases can be broadly categorized as environmental, nutritional, or genetic.

Environmental diseases are the most important in commercial aquaculture. Environmental diseases include low dissolved oxygen, high ammonia, high nitrite or natural or man-made toxins in the aquatic environment. Proper techniques of managing water quality will enable producers to prevent most environmental diseases. There are separate IFAS publications which address water quality management in greater detail.

Nutritional diseases can be very difficult to diagnose. A classic example of a nutritional disease of catfish is "broken back disease," caused by vitamin C deficiency. The lack of dietary vitamin C contributes to improper bone development, resulting in deformation of the spinal column. Another important nutritional disease of catfish is "no blood disease" which may be related to a folic acid deficiency. Affected fish become anemic and may die. The condition seems to disappear when the deficient feed is discarded and a new feed provided. Additional information on nutrition of fish is available through your aquaculture veterinary extension specialist.

Genetic abnormalities include conformational oddities such as lack of a tail or presence of an extra tail. Most of these are of minimal significance; however, it is important to bring in unrelated fish for use as broodstock every few years to minimize inbreeding.

What to Do if Your Fish are Sick

If you suspect that fish are getting sick, the first thing to do is check the water quality. If you do not have a water quality test kit, contact your county extension office; some counties have been issued these kits, and your extension agent may be able to help you. If your county is not equipped with a water quality test kit, call the aquaculture extension specialist nearest to you (see the list at the end of this publication). Anyone contemplating commercial production of fish should invest in a water quality test kit and learn how to use it. An entry level kit for freshwater aquaculture can be purchased for about $200, and can save thousands of dollars worth of fish with its first use.
Low oxygen is a frequent cause of fish mortality in ponds, especially in the summer. High levels of ammonia are also commonly associated with disease outbreaks when fish are crowded in vats or tanks. Separate extension fact sheets are available that explain oxygen cycles, ammonia cycles, and management of these water quality problems. In general, check dissolved oxygen, ammonia, nitrite, and pH, during a minimum water quality screen associated with a fish disease outbreak. The parameters of significance include total alkalinity, total hardness, nitrate (saltwater systems) and chlorine (if using city water).

Ideally, daily records should be available for immediate reference when a fish disease outbreak occurs. These should include the dates fish were stocked, size of fish at stocking, source of fish, feeding rate, growth rate, daily mortality and water quality. This information is needed by the aquaculture specialist working with you to solve your fish disease problem. Good records, a description of behavioral and physical signs exhibited by sick fish, and results of water quality tests provide a complete case history for the diagnostician working on your case.

Professional assistance is available to Florida residents through the Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences (IFAS) at the University of Florida; the Department of Agriculture and Consumer Services, Division of Animal Industries and Division of Aquaculture, as well as several private laboratories and veterinary practices. A list of public resources is included at the end of this publication.

If you decide to submit fish to a diagnostic laboratory you should collect live, sick fish, place them in a freezer bag (without water), and ship them on ice to the nearest facility. Small fish can be shipped alive by placing them in plastic bags which are partially filled (30%) with water. Oxygen gas can be injected into the bag prior to sealing it. An insulated container is recommended for shipping live, bagged fish as temperature fluctuations during transit are minimized. In addition to fish samples, a water sample collected in a clean jar should also be submitted. Detailed information on submitting samples is available in UF/IFAS Fact Sheet FA-55, Submission of Fish for Diagnostic Evaluation.

Determining if Your Fish are Sick

The most obvious sign of sick fish is the presence of dead or dying animals. However, the careful observer can usually tell that fish are sick before they start dying because sick fish often stop feeding and may appear lethargic. Healthy fish should eat aggressively if fed at regularly scheduled times. Pond fish should not be visible except at feeding time. Fish that are observed hanging listlessly in shallow water, gasping at the surface, or rubbing against objects indicate something may be wrong. These behavioral abnormalities indicate that the fish are not feeling well or that something is irritating them.
In addition to behavioral changes, there are physical signs that should alert producers to potential disease problems in their fish. These include the presence of sores (ulcers or hemorrhages), ragged fins, or abnormal body confirmation (i.e., a distended abdomen or "dropsy" and exopthalmia or "popeye"). When these abnormalities are observed, the fish should be evaluated for parasitic or bacterial infections.

The Significance of Fish Disease to Aquaculture

Fish disease is a substantial source of monetary loss to aquaculturists. Production costs are increased by fish disease outbreaks because of the investment lost in dead fish, cost of treatment, and decreased growth during convalescence. In nature we are less aware of fish disease problems because sick animals are quickly removed from the population by predators. In addition, fish are much less crowded in natural systems than in captivity. Parasites and bacteria may be of minimal significance under natural conditions, but can cause substantial problems when animals are crowded and stressed under culture conditions.
Disease is rarely a simple association between a pathogen and a host fish. Usually other circumstances must be present for active disease to develop in a population. These circumstances are generally grouped under the umbrella term "Stress" .
Stress is discussed in greater detail in the UF/IFAS Extension Circular 919 Stress - Its Role in Fish Disease. Management practices directed at limiting stress are likely to be most effective in preventing disease outbreaks.

When to Terminate a Bath Treatment

No chemical used in aquaculture is completely harmless to fish. Treatments are designed to be more harmful to the problematic organism (ie. bacteria, protozoan) than to the host organism (ie. fish) which results in successful elimination of the pathogen with minimum damage to the fish. For some chemicals, particularly copper sulfate, the difference in chemical concentration which is lethal to the pathogen and that which is lethal to the fish is small. If fish show any signs of distress during the treatment (ie. trying to leave the water, gasping at the surface) the treatment should be terminated immediately and fish placed in clean water.
If fish are in a pond and have been treated with a low concentration of chemical (prolonged bath) there is nothing that can be done to remove the chemical if it has been improperly applied. Again, one way to help avoid losing a pond of fish by accidentally applying too much chemical is to have the amount of chemical to be applied calculated independently by two people. Volumes of ponds should be known and the amount of chemical needed to treat each individual pond should be calculated and recorded for easy reference. Errors are best avoided by preparing for a disease situation before it happens, rather than frantically calculating treatment rates and locating chemical suppliers when a disease is in progress.

How to Add Chemicals to the Bath Treatment

Before applying chemicals double check the chemical you are using, the concentration to be delivered, and ideally, two people should independently calculate the amount of chemical to be added. Proper calculation of concentration is contingent upon accurate determination of volume of water to be treated. If you are uncertain as to the volume of water to be treated take the time to measure the size of the pond or container so that volume can be accurately determined.
Addition of chemicals to water containing fish must be done carefully so that all the chemical is mixed uniformly throughout the water column. If the chemical is not thoroughly mixed, "hot spots" (areas of high concentration of chemical) may be formed which can damage, or kill, fish. To ensure uniform application, dry chemicals can be dissolved in water prior to, or during, application. In some ponds, aerators can be used to help distribute chemicals throughout the water column. Personnel handling chemicals should be encouraged to wear protective clothing.

Sick fish are often weak and may not tolerate chemicals at the concentrations recommended. Never leave fish unattended during treatment. Nets and other equipment used to handle sick fish must be sanitized before being used again.

When to Use Bath Treatments

The aim of most successful bath treatments is to eliminate external infections. External infections occur on the gills, skin, and fins of fish. They can be of parasitic, bacterial or fungal origin. In contrast, use of bath treatments to treat internal infections, particularly systemic bacterial disease, is not generally recommended. Medicated feeds are preferred for treating internal problems. However, if fish are not eating then a bath treatment may be the only method available to administer medication.
The chemicals which are most commonly used for bath treatments are potassium permanganate, formalin, copper sulfate, and salt.

Bath Treatment ...rawatan untuk ikan yang diserang penyakit

Types of Bath Treatments

There are three basic types of bath treatments: dips (less than 1 minute), short-term baths (about 1 hour), and prolonged baths (indefinite). The difference between these bath treatments is the concentration of the chemical applied and the period of time that the fish are in contract with the chemical.

A Dip is just what the name implies. The fish is dipped into a concentrated chemical bath for a short period of time, often less than one minute. Prolonged exposure to the chemical at the high concentration delivered in a dip would be fatal to the fish. Because fatalities can easily result from an improperly administered dip treatment, and because sick fish are generally intolerant of stressful situations, dip treatments are often avoided by many aquarists. An exception to this may be the use of salt water dips when moving fresh water fish, and the use of fresh water dips when moving salt water fish. These techniques are discussed in a separate IFAS Fact Sheet, Use of Salt to Treat Fish Diseases.

A Short-Term Bath means that the fish are subjected to a moderate chemical concentration for a period of time ranging from 30 minutes to several hours. This is an excellent method for administering many medications to fish kept in aquaria, tanks, or raceways. The duration of exposure to the chemical will be determined by the chemical used, the concentration of chemical used, and the facility in which the fish are housed. In most cases, water flow and filtration are shut down while the chemical is in contact with the fish. This prevents rapid dilution of the chemical by in-flowing water and also prevents the chemical from coming in contact with bacteria in the biofilter. If the water flow and circulation is shut down during the treatment, water quality should be monitored to prevent harmful increases in ammonia concentration. Vigorous aeration should always be maintained during treatment.

A Prolonged Bath
means that small concentrations of chemical are applied and left in the water on a permanent basis, where it will eventually break down and disappear. This is the only method of administering a bath treatment to pond fish. Because of the low concentrations of chemical applied, a prolonged bath is often the least expensive and safest way of administering a chemical bath. A prolonged bath is not recommended, however, when fish are crowded in a relatively small area such as a tank or vat. Shutting off water flow or filtration for an extended period of time (more than 2-4 hours) under tank conditions is likely to result in serious degradation of water quality which could further stress, or kill directly, the fish.

Fish disease - virus

Infection Pancreatic Necrosis (IPN)
Spring Viraemia of Carp (SVC)
Epizootic Haematopoeitic Necrosis (EHN)
Infectious Haematopoietic Necrosis (IHN)
Viral Encephalopathy and Retinopathy ( VER)

Infectious Pancreatic Necrosis

Aetiology: Birnavirus
Characteristics: replicates in cytoplasm
Epizootiology: as it applies to salmonid disease
Reservoir: Carrier fish which secrete virus in the faeces or sexual products
Transmission: eggs, water, direct contacts, piscivors can transport virus
Occurance: any age
Geographic distribution: Japan, Korea, North America, Europe, Taiwan and Chile
Grass carp: Gross signs & pathology: Massive mortalities in grass carp fingerlings, with lower levels of mortality in yearlings, exophthalmia and haemorrhagic areas at the base of the operculum, haemorrhages in the musculature , mouth , intestine , liver and kidney
(Trout): Gross Signs & Patho : whirling about long axis, weak respiration, darkening, exophthalmia , abdominal distention , pancreatic necrosis, multiple petechiae in omental fat, pale liver & spleen, empty gut & white mucus in the intestine
Histopath: characteristic changes in pancreatic acinar cells; necrosis, pyknotic nuclei with a clear halo around them and the surrounding adipose cells wall still be normal
Dx: isolation & presence of typical CPE in cell culture , use RTG-2 cell lines , CPE- stringly lysis; typical histopathology; confirmed with VNT
Ctl: reduce stress, eradication from farm (certified broodstock), disinfect eggs, rear fry in spring water, disinfect tanks and ponds, quarantine

Spring Viraemia Of Carp

Aetoilogy : Rhabdovirus carpio and Aeromonas hydrophila
Characteristics: replicates in cytoplasm
Epizootiology: species affected-cyprinids
Reservoir: carrier fish, latent infections as the virus is only detected in outbreak Transmission: via water, highly infectious
Occurrence: any age affected
Classically seen in the spring as the temperatures rise to greater than 15-20C
Geographic distribution : Europe
Gross signs : darkening, exophthalmia, abdominal distension, lethargy
Then- lie on sides, distended anus, faeces castes trail in water , petechial haemorrhages on gills, skins and fins
Pathology : fibrinous peritonitis, petechial haemorrhages over internal organs , catarhal enteritis, asites
Histopathology: focal haemorrhages, necrosis of haematopoietic elements in kidney & spleen, submucosal odema of intestine & stomach
Confirmed by isolation of virus
Use FHM, BB or RTG cell lines
Serum neutralization test
Note that history , gross signs and histopathology are all non specific
Prevention and Control:
Prophylatic use of antibiotics
Quarantine country
Treatment: experimentally –injected antibiotics reduce mortalities


Cottonwool disease
Aetiology: Lymphocyctis virus
Replication on fibroblast
Epizootiology : Species effected- many species , marine most commonly infected , but also freshwater & ornamental fish
Reservoir: infected fish
Transmission: direct contact
Occurance: lesions seen in 5-30% of some wild fish populations
Geographic distribution: worldwide
Gross signs: the virus infection does not usually result in death , economics losses occur due to consumer rejection of the affected fish, raised growths that appear to consist of small many white nodules on the skins and fins, occasionally single white nodules are seen in the internal organs, over time these lesions grow, necrotise and become secondarily infected by bacteria.
Pathology: lesions consists of massively enlarged fibroblasts (2mm).
Histopathology: dark blue inclusions in cytoplasm, 3 months after infection see a host response , a hyaline capsule around the enlarged fibroblast
Diagnosis: gross signs and histopathology
Isolation can be difficult unless primary cell lines from infected species are used
Prevention & Control: not a major problem but common
If present at a cage site, remove infected fish and disinfect nets etc.
Treatment: At early stage of infection by surgically removing the raised growths and disinfecting the resulting wound with acriflavine.

Epizootic Haematopoeitic Necrosis ( EHN)

Aetiology: Iridovirus
Host range: Redfin perch ( Perca fluviatis), Rainbow trout ( Oncorhynchus mykiss)
Mosquito fish ( Gambussia affins), Silver perch ( Bidyanus bidyanus)
Geograhics distribution: restricted to mainland Australia
Clinical Signs: No specific clinical signs
Mortalities are characterized by necrosis of liver ( with or without white spots), spleen , haemtopoeitic tissue of kidney and other tissue
Distruption of blood function, leads to osmotic imbalance, haemorrhagic lesions, buildup of body fluids in body cavity
Assoc. water quality, temperature
Diagnosis: Isolation of EHNV, ESV and ECV in cell culture
Confirmation: neutralization test, indirect fluorescent antibody test, enzyme-linked immunosorbent assay ( ELISA), polymerase chain reaction (PCR) & sequencing

Infectious Haematopoietic Necrosis

Aetiology: Rhabdovirus
Host range: rainbow or steelhead trout & Pacific Salmon
Geographical Distribution: North America, Europe & Asia
Transmission: vertical & horizontal
Clinical Signs: dark discolouration of body, distended abdomen, haemorrhage at the base of fins, operculum and around eyes “ pop-eye”, weaked swimming ability, white discharge from anus
Pathology: IHNV multiplies in endothelial cells of blood capillaries, spleen, kidney cells, which results in osmotic imbalance as well as systemic haemorrhagic lesions pale internal organs and or pin point bleeding in the musculature and fatty tissues
Kidneys, spleen, brain and digestive tract are the sites where virus is most abundant during advanced infection
Diagnosis: gross observations, histopathology, virology, ELISA, TEM

Viral Encephalopathy and Retinopathy( VER)

Also known as Striped Jack Nervous Necrosis Virus ( SJNNV), Viral Nervous Necrosis ( VNN), Fish Encephalitis Virus ( FEV)
Aetiology: nodavirus
Host Range: cultured marine fish ( seabass, turbot, halibut, Japanese parrotfish, red- spotted grouper, striped jack, Japanese flounder, brown spotted grouper )
Geographic Distribution: Asia, Mediterranean, Pacific
Clinical Signs: VER affects nervous system
Abnormal swimming behaviour, swimming bladder hyperinflation, reduced feeding, changes in colouration & mortality
Diagnosis: gross observations, histopathology ( vacuolization in brain or retinal tissues)

Fish Disease- Fungus

Integumentary Mycoses

Gills or skin following some kind of damage to the epithelium
Agent: Saprolegnia sp.
Culture: sabourauds agar
Epizootiology: Species affected-all freshwater sp & occasionally brackishwater/marine fish
Reservoir: normal inhabitant of water and oil
Transmission: motile zoospores in water
Occurance: any age
Important problem in hatcheries and aquarium
Never a primary infection, always follows damage to the gills/ skin or a physiological change
Geographic distribution: worldwide
Gross signs: circular, superficial, grayish white, cotton wool like growths on the fish these collapse when the fish is removed from water
If bacteria also present, lesions have haemorrhagic appearance
If gills affected, see signs of respiratory insufficiency
Pathology: death due to osmotic shock, hyphae invade stratum spongiosum & spread laterally over the dermis, epidermis shows oedema, spongiosis & necrosis
Diagnosis: gross signs, fungi isolated & cultured
Prevention and control : As Saprolegnia is an ubiquitous and secondary invader, control of primary factors reduce the incidence of fungus infections
Treatment: Malachite green, Methylene blue, Salt

Fish DIsease Again

Fish Diseases – Bacteria

1. Cytophagaceae
• Columnaris Disease

2. Enterobacteriaceae
• Edwardsiela septicaemia
• Enteric Redmouth (ERM)

3. Vibrionaceae
• Vibriosis
• Furunculosis
• Motile Aeromonad Septicaemia

4. Pasteurellaceae
• Pasteurellosis

5. Pseudomonadaceae
• Pseudomonas

6. Gram positive Fish Pathogens
• Streptococcal Infections

7. Acid Fast Pathogens
• Mycobacteriosis

Columnaris Disease

• Agent: Flexibacter columnaris
• Morphology: Gram negative, long,thin,aggregates in mounds on slides
• Culture: grows well on cytophaga agar, yellow colonies, fried egg appearance, optimum temp 15C.
• Epizootiology: 36 different species, salmonids and catfish most significant
• Reservoirs: wild fish
• Transmission: horizontal, water, experimental via moribund carcasses
• Environmental factors: elevated temps, temps depends on host species, usually 15C, severity increases with temp, high pH, hard water, organic matter, cleanliness important, crowding

• Patho: lesions confined to head, back, gills, starts as raised whitish spot distal on fins, gills; gradually develops into larger ulcer, bacteria isolated from leading edge of ulcer; skin eventually erodes away, exposing muscle; death rapid if necrosis/lesions are on gills due to respiratory problems, highly virulent strains cause death w/out lesions

• Dx: long, thin gram negative rods from lesions; rhizoid colonies on cytophaga agar; haystacking, clinical signs & serology
• Ctl; improved environment, cooler water temp, increased oxygenation , decreased crowding, organics, reduced stress
• Tx: internal via oxytetracycline in feed, sulfonamides

Edwardsiella Septicemia

• Agent: Edwarsiella tarda
• Morphology: Gram negative, rod
• Culture: gram negative rod, motile by flagella, grows well on most standard media(TSA, BHI), produces small transparent and smooth circular colonies at 35C ferments glucose and produces gas , indole positive (diff. From E.Ictaluri)
• Epizootiology: southern U.S, SE Asia , Pacific NW, many warmwater species of fish
• Reservoir: pathogen of or can be carried by many vertebrates and invertebrates
• Transmission: horizontal
• Environmental factors: higher than 30C water, organics, crowding; salmonids at temps greater than 20C

• Patho: fish large 38 cm( high value), slow progress, low mortality unless fish stressed (5--50%mort) , causes development of gas filled abscesses containing sulfide; mild infections exhibits small cutaneous postlateral lesions, progressing as abscesses in muscles of flank or caudal peduncle, lose control of posterior portion of body
• Dx: isolation from kidney into TSA or BHI; presumptive as gram negative, motile rod, motile via use of flagella, catalase +ve, cytochrome oxidase –ve, & serology
• Ctl: good culture environment
• Tx: oxytetracyline at 2.5g/45 kg feed /fish/day for 10 days

Enteric Redmouth Disease(ERM)

• Agent: Yersinia ruckeri
• Morphology: Gram negative , rod , motile by flagella at 18 - 27C, can become filamentous in order cultures
• Culture: std media, 22-25C, cytochrome oxidase –ve, no gas/H2 S in TSI, ferments glucose
• Epizootiology: originally Idaho, now apparently ubiquitous; mainly rainbows but also cyprinids
• Reservoirs: natural host , carriers with low grade mortality
• Transmission: horizontal
• Environmental factors: large scale epizootics occur due to stress , low DO, poor environment , grading ; reduced 14C
• Pathology: infected fish become sluggish, darker; severe congestion /hemorrhages of tissues of head /mouth, stomach filled w/water colorless fluid, intestines w/yellow fluid , petechial hemorrhages of internal orgs, spleen dark/enlarged
• Dx: isolation from kidney onto TSA or BHI plates at 20-25C for 24-48 h, Gram negative, motile rod, cytochrome oxidase negative , no H2S in TSI & serology
• Ctl: prevented from avoidance , hygiene, detection of carriers; immunization available and best management tool; can disinfect eggs w/iodophires (25 ppm), sulfamerazine + oxytetracycline ( 20g/100kg/f/d; 5g/100kg/f/d for 5 days each)

Pseudomonas fluorescens

• Agent: Pseudomonas fluorescens
• Morphology: Gram negative , rod motile via polar flagellum
• Culture: std media , round glistening colonies w/undulating edge, radial striations, easily seen green pigment under UV light (pseudomonas F agar), cytochrome oxidase +ve, catalase +ve, strict aerobe, grows at 18-25C
• Epizootiology: worldwide, all fish susceptible, problem for aquarium fish
• Reservoirs: mud and water; infected or carrier fish and others( frog)
• Transmission: horizontal
• Environment factors: stress, mainly elevated temps
• Patho: hemorrhages and necrosis of internal organs & external lesions
• DX: isolation from kidney on TSA or BHI &id
• Ctl: remove stressor
• Tx: oxytetracycline at 50-75 mg/kg/f/day for 10 days

Motile Aeromonad Septicaemia (MAS)

• Agent: taxonomy confused, Aeromonas hydrophila (more than 10 other species claimed); G-motile rod w/polar flagella; oxidase +ve, catalase +ve, glucose fermenter
• Culture: TSA, BHI; can grow at 4C but best at 18-25C; white, circular, convex colonies, often confused w/Citrobacter
• Epizootiology:worldwide in fw, all fw species susceptible, others such as frogs, alligators, snails , prawns
• Reservoirs: freshwater w/high organics loads , usually in sewage, normal gut flora of healthy fish; diseased fish/frogs; survivors are carriers
• Transmissions:horizontal
• Environment factors: stress from crowding, variable temps, changes in weather, rough handling, low DO, high organics
• Patho: usually hemorrhages + necrosis internal organs + necrotics lesions on skin/muscle = G-septicemias
• Superficials circular or grayfish- red ulcerations
• Lesions around mouth similar to ERM
• Hemorrhages of fins ,exopthalmia
• Internal pathology: swollen, soft kidney; petechiae of musculature, intestines free of food
• Dx: isolation from kidney into TSA or BHI, Gram negative, motile rod, cytochrome oxidase +ve, ferments in glucose, no fluorescent pigment
• Ctl: prevention via good management
• Tx: oxytetracycline at 50-75mg/kg fish/ day for 10 days


• Agent: Aeromonas salmoncida (produced pigment)
• Morphology: Gram negative, rod, nonmotile
• Culture: TSA/BHI, brown pigment, grows well at 18-25C, small white round raised convex colonies , oxidase+ve, non-motile, ferments glucose but no gas
• Patho: both virulent and avirulent strains, produces endotoxin
• Epizootology:salmonids cultured in fw
• Reservoirs: obligate fish pathogens, found in waters w/infected or carriers fish
• Transmission: horizontal
• Environmental factors: severity increases w/temp, nutrition, handling stress
• Patho: similar to other G-, septicaemia conditions w/hemorrhaging, necrosis of internal organs, external lesions
• External patho: focal necrosis in muscle develops to abscess, hemorrhages at base of fins, bloody discharge from vent, bleeding from gills
• Intenal patho: petechiae in body musculature, congestion of posterior intestine, no inflammatory response
• Dx: isolation from kidney into TSA, BHI; gram negative, non-motile rod, brown diffusible pigment, oxidase +& serology
• Ctl: avoidance via clean water/fish; several vaccines on the market
• Tx: oxytetracyline at 50-75mg/kg fish/day for 10 days


• Agents: Vibrio parahaemolyticus, V.alginolyticus, V. anguillarum
• Morphology: Gram negative, curved/ straight rods, motile with a single polar filament
• Epizootiology: all marine /brackish water fish, including ornament marine fish
• Reservoir: wild fish carriers of pathogenic strains & as a normal inhabitant of the GI tract
• Transmission: horizontal
• Occurance: all ages assoc with high temperatures, rapid salinity changes, handling & ectoparasite damage
Disease is always preceeded by some from of stress
Level of mortalities & acuteness of disease depends on temperature, strains virulence, fish species & stressor
100% mortalities in fry and fingerlings, but in epizootic more than 50% mortality
• Clinical signs:
• Peracute disease: only seen in young fish, anorexia, darkening of hyperaemia of the skin, sudden death
• Acute & Chronic disease: older fish, darkening, lose balance & jump out of water, hyperaemia around vent, sides of operculum , caudal fins & base of fin , haemorrhage of the eyes & gills, petechia on the body surface which develop into haemorrhagic ulcers which may extend down into the skeletal muscles in the chronic forms of the diseases , exophthalmia is occasionally seen.

• Patho: haemorrhages through out the internal organs, hyperamics intestinal tract, enlarged and liquefied spleen, liquefaction of the kidney.

• Histopathology: foci of necrosis in the liver, spleen and kidney
In peracute disease see a severe cardiac myopathy

• Diagnosis: based on clinical signs, pathology and history
Confirmed with isolation
Primary isolation should be made on TSA(1.5%) NaCl at 20-25C and 24-48h
A presumptive diagnosis can be made if the isolate is a Gram negative , short /curved rod, motile , cytochrome oxidase +ve, produces acid but no gas in glucose O/F medium
Confirmed if the TSA isolate is sensitive to vibrostat 0/129
Antisera are available for vibrio in temperate regions

Further biochemical testing for further identification

• Prevention & Control:

Avoid handling & high stocking densities at risk periods of high temperatures or sudden salinity changes
General sanitation procedures
Commercial vaccines available
Treatment: Antibacterial can be incorporated in feeds
But the diseased fish may have stopped eating and bacteria maybe resistant to the antibacterial used

Vibrio Infections of Fish

Vibrio infections usually occur in fish from
marine and estuarine environments, and have been
reported throughout the world. Occasionally,
vibriosis is reported in freshwater fish. The disease
can cause significant mortality (>=50%) in fish
culture facilities once an outbreak is in progress.
Common names for Vibrio infections of fish include
"red pest" of eels, "salt-water furunculosis", "red
boil", and "pike pest". Vibrio infections can spread
rapidly when fish are confined in heavily stocked,
commercial systems and morbidity may reach 100%
in affected facilities.

The disease is caused by gram negative bacteria
in the family Vibrionaceae. This group of bacteria
includes two important genera which can be
significant fish pathogens. The genus Aeromonas
includes several species which are important
pathogens of freshwater fish, although they
occasionally cause disease in marine species.
Bacteria in the genus Vibrio are important pathogens
of marine and brackish water fish, although they
occasionally are reported in freshwater species.
Seven species of Vibrio have been associated with
disease in fish:

• V. anguillarum (isolated most commonly from
marine and brackish water fish);
• V. ordalli (an atypical strain of
• V. anguillarum , sometimes referred to as
Biotype 2);
• V. damsela (isolated from damsel fish);
• V. carchariae (isolated from sharks);
• V. vulnificus (reported in Japanese eels); and
• V. alginolyticus (reported from cultured
seabream in Israel).

A new, extremely pathogenic Vibrio infection of
cold-water marine fish (i.e., salmon) is caused by V.
salmonicida and is referred to as "cold-water vibrio"
or "hitra" disease. Cold-water vibrio has not been
reported in warm-water fish and will not be discussed
further in this publication.

Vibrio species are also known to cause disease
in humans, most often following the consumption of
contaminated shellfish. Most serious illness is usually
limited to individuals with a suppressed immune

Signs of Infections
The signs of vibriosis are similar to many other
bacterial diseases of fish. They usually start with
lethargy and a loss of appetite. As the disease
progresses, the skin may become discolored, red and
necrotic (dead). Boil-like sores may appear on the
body, occasionally breaking through the skin surface
resulting in large, open sores. Bloody blotches
(erythema) are common around the fins and mouth.
When the disease becomes systemic, it can cause
exopthalmia ("pop-eye"), and the gut and rectum may
be bloody and filled with fluid. It should be noted that
all of these "signs" can be caused by other bacterial
diseases, and are not proof of a Vibrio infection.


Before any treatment with antibiotics, a thorough
investigation of water quality and husbandry
practices should be conducted. Removal of
underlying problems is essential to successful
resolution of the problem. Occasionally, removal of
contributing factors (i.e., poor water quality) will be
all that is required to control the infection, but in most
cases it is prudent to treat an active Vibrio outbreak
with antibiotic therapy.
The selection of an antibiotic should be based on
results of an in vitro sensitivity test. There are two
antibiotics which have been approved by the Food and Drug Administration (FDA) for use in food fish (catfish and salmonid.)

Terramycin contains the antibiotic oxytetracycline. It
is sold for fish in a sinking feed and should be fed for
10 days. Fish which have been fed Terramycin should
not be eaten for at least 21 days following treatment
(the legal withdrawal time) to ensure complete
elimination of drug residue from edible tissue. Romet
is a potentiated sulfonamide which contains two
drugs, sulfadimethoxine and ormetoprim. It is sold
for fish in a floating feed and should be fed for 5 days.
The withdrawal time of Romet for catfish is only 3
days because the drug is bound in the skin of the fish
which is removed when catfish are cleaned. In
salmonids, however, the withdrawal time is 6 weeks
because the fish are not skinned during processing.
Either drug will be effective if the strain of Vibrio is
sensitive to it and if sick fish ingest enough
medication to maintain the drug in the bloodstream
throughout the treatment period.
In pet fish, the traditional treatment for bacterial
disease has been the addition of antibiotics to tank
water. This practice should only be pursued as a last
resort. Antibiotics should be delivered to fish in
medicated feeds or by injection. Flake foods which
contain Terramycin or Romet are commercially
available through pet retail outlets for use in
aquarium fish. Because there is no FDA-approved
antibiotic available for use in pet fish, veterinary
supervision of antibiotic therapy is recommended. If
fish do not respond to antibiotic therapy within 48
hours a sample of sick fish and water should be sent
to a fish disease diagnostic laboratory to confirm the
original diagnosis and determine whether additional
problems, such as parasitism, may also be present.

Penyakit yang boleh menyerang Lintah


Reported to be vectors of trypanosomes and Cryptobia in freshwater fish. Suspected of being
capable of transmitting Trypanosoma brucei and T. equiperdum to humans. Concern about
passing strains of hepatitis prevents reuse of medicinal leeches.

Types of Leeches

•500 species of leeches world wide
•63 species in North America
•35 species in Ontario

•One species is the primary leech used for bait
–Bait leech or ribbon leech (Nephelopsis obscura)

•Other swimming leeches commonly caught in traps

–Tiger leech (Erpobdella punctata)
–Horse leech (Haemopsis sp)
–Medicine leech (Macrobdella decora)

Ribbon Leech
•Most common
•Aquatic and active swimmer.
•Slate gray or gray brown in colour
•Body flattens to firm ribbon-like edges


–Ponds and marshes rich in organisms.
–Shallow littoral zone.
–Feeds mainly at night.

Life History

–Reproduce in mid summer of second year.
–Develop in safety of cocoon.
–Dormant over winter
–Trappable size following spring

–Feeds on small invertebrates.
–Predacious –jaws and muscular pharynx
–Opportunistic feeder

Horse leech

–Is used for bait
–Predator and scavenger feeder
–Greenish to dark brown
–Identified by five pair of small black eyes on top of head.

Medicine leech

–Black with reddish orange spots on back
–Reddish orange belly

Leech BioloGy

Other State Of Leeches

Annelids or segmented worms
•32 segments regardless of size
•Suckers on each end of their body
•Pigmented skin
•Dull gray or black to bright orange
•Active swimmers and creepers

Parasitic or predatory
•Parasitic blood suckers gorge and may remain dormant for weeks
•Predatory leeches feed on worms, invertebrates, insects, worms and snails.

Where to Find Leeches

•Primarily fresh water.
•Warm protected shallows.
•Maximum abundance –2Metres
•Avoid Light.
•Water temperature is not considered a limiting factor.
•Low oxygen levels deplete leech growth.
•Leeches retreat to deep water in the winter
•Most abundant in ponds that do not contain fish.
•Ponds with bullheads, perch or sunfish contain few leeches.
•Fat head minnows benefit leech habitat.
•Ponds shallow with silt
•Substrates and abundant aquatic vegetation near shore.
•Beaver ponds are ideal habitat

Thursday, October 11, 2007

Pemakanan Lintah

Secara amnya, lintah menghisap darah semua hidupan.

oleh itu, saya bagi sedikit list sekadar info.

sebarang keraguan, boleh diaju kan soalan..

Jenis-jenis makanan lintah::






Organisma Kecil


kura - kura

Hati ayam ( tetapi boleh menjejas kan kualiti air)

Pemberian makanan perlu lah bersistematik supaya tiada gangguan pada kualiti air.

Seeloknya Jangan terlalu Mengambil Mudah Selepas Pemberian makanan.


Aspek Penting Yang perlu Diambil ::

Keperluan Tanah dan Iklim

Penyediaan Tanah

Kualiti air


Penjagaan dan Pemakanan

Habitat ?Lintah yang sesuai@@

Thursday, October 4, 2007

list of engine sites

List of Search Engines

You may submit your site URL to these search engines for Free. If you lack the time, submit your site to the top few leading search engines.

Yahoo! Search
Microsoft Live Search
Alexa Web Search
Baidu (Chinese search engine)
Scrub the Web
Splat Search
email Mozdex
Abacho (European search engine)

Tuesday, October 2, 2007


Bioremediation is a combination of two words – bio, short for biological, and remediation, which means to remedy.
Bioremediation usually refers specifically to the use of microorganisms.
Process that uses naturally occurring or genetically engineered microorganisms such as yeast, fungi and bacteriato transform harmful substance into less toxic or nontoxic compound.
Bioremediation uses living organisms to clean up contaminated soil or water.

Types of Bioremediation
Intrinsic Bioremediation

Nutrients and oxygen - in a liquid or gas form - are added to contaminated water or soil to encourage the growth and activity of bacteria already existing in the soil or water.

The disappearance of contaminants is monitored to ensure that remediation occurs.

Bioaugmentation is more commonly and successfully used on contaminants removed from the original site, such as in municipal wastewater treatment facilities.

To date, this method has not been very successful when done at the site of the contamination because it is difficult to control site conditions for the optimal growth of the microorganisms added.

Bioaugmentation is more commonly and successfully used on contaminants removed from the original site, such as in municipal wastewater treatment facilities.

To date, this method has not been very successful when done at the site of the contamination because it is difficult to control site conditions for the optimal growth of the microorganisms added.

Intrinsic Bioremediation
Also known as natural attenuation, this type of bioremediation occurs naturally in contaminated soil or water.

This natural bioremediation is the work of microorganisms and is seen in petroleum contamination sites, such as old gas stations with leaky underground oil tanks.

Anabolism – Building Up
In anabolism, chemicals taken up by the microorganism are used to build various cell parts. Carbon and nitrogen are the basic chemicals in the proteins, sugars and nucleic acids that make up microbial cells.

Microorganisms take up carbon and nitrogen from the soil, water, and air around them. In order to take up nutrients and make them into cell parts, a microorganism needs energy. This is where catabolism comes in.

Catabolism – Breaking Down

Catabolism allows microorganisms to gain energy from the chemicals available in the environment.

Although most microorganisms are exposed to light and to chemical energy sources, most rely on chemicals for their energy.

When chemicals break down, energy is released. Microorganisms use this energy to carry out cellular functions, such as those involved in anabolism

Anabolism and Catabolism's Role in Bioremediation

Chemicals present at contaminated sites become part of the anabolism and catabolism process.
For example, hydrocarbons (part of the carbon family) present at sites with petroleum products can be taken up by microorganisms and used as building blocks for cell components.

Other chemicals that are important to a microorganism include chemical compounds in the phosphorus, potassium, calcium and sodium group.

Microorganisms also need trace elements of other chemicals, including chromium, cobalt, copper, and iron, all of which can be available in abundance at contaminated sites.

Natural Defenses Against Infection

First line defense line against disease is skin, mucus, and other passage connection connecting internal and external environment
If the pathogen pass this first line defense, than the second line defense, which is provided by natural or innate immune mechanisms.
In this case, our own cells and the chemicals they produce seek out, identify and eliminate the pathogen.
These very general and non-specific responses are critical to the maintenance of good health.

On occasion, a pathogen can get past fish bodies’ primary protective mechanisms if it is present in very large numbers or if it has evaded or suppressed these processes.
Stronger protection is needed and we respond by mounting an acquired immune reaction specific to the pathogen.
These responses involve a variety of types of cells found in the blood and tissues, and can require a week or more to become established.
Acquired immunity consists of antibody and cell-mediated responses.

An acquired immune response can result in either short-term or long-term protection against a specific pathogen and, perhaps, against some of its close relatives.
In the case of long-term protection, re-exposure to the same pathogen weeks, months or years later reactivates the response mechanisms laid down during the original exposure.
This reactivation leads to rapid, effective elimination of the agent, often without clinical symptoms or signs of infection. When specific immunity results from unintentional exposure to agents in the environment, we refer to the resulting protection as being passively acquired immunity.

Intentional exposure to such an agent or its components through vaccination is known as actively acquired immunity
A humoral response and a cellular response. The humoral response is the stimulation of serum protein molecular synthesis homologous specific to the antigen causing the synthesis. These serum protein molecules are called antibodies

A weak bacteria will enter into the body of the fish
All potential pathogens contain antigens. The introduction of antigens by a pathogen is what stimulates the antibody response of the host
The immune system will be respond to the bacteria, and reproduce the antibody of the bacteria.

The specific immune will be produce to created future protection
The cellular response to antigen stimulation is a sensitization of cellular elements of the reticuloendothelial system.

Vaccine system

Vaccines are various preparations of antigens derived from specific pathogenic organisms that are rendered non-pathogenic.

They stimulate the immune system and increase the resistance to disease from subsequent infection by the specific pathogen.


The main component of the immune system is the lymphatic system. Small organs called lymph nodes help carry lymph fluid throughout the body.

Lymph fluid contains lymphocytes and other white blood cells and circulates throughout the body.


Chromosomes are composed of a series of genes linked together on a molecule of DNA. If the combination of alleles on a chromosome could not be changed the genetic variability available for natural selection would be severely reduced.

The new combinations of chromosomal alleles are a major source of the genetic variation used in natural selection. Other recombinant based phenomenon include the generation of antibodies and the movement of "jumping genes" to new chromosomal locations.
Recombinant vector vaccines. A vaccine vector or carrier is a weakened bacterium into which harmless parts of genetic material from another disease-causing micro-organism have been inserted.

Different types of vaccines exist

Inactivated vaccines are the most common in aquaculture. They are produced by inactivating the disease-causing micro-organism with chemicals or heat.

Live, attenuated vaccines. To make a live, attenuated vaccine, the disease-causing microorganism is grown under special laboratory conditions that cause it to lose its virulence or disease-causing properties. Intervet’s Aquavac ESC®, a vaccine used against Edwardsiella ictaluri in Channel catfish (Ictalurus punctatus) in the USA is an example.

Subunit vaccines are a more modern type of vaccine, developed from antigenic fragments that are able to evoke an immune response. Subunit vaccines can be made by purification of parts of the actual micro-organism or they can be made in the laboratory using genetic engineering techniques. An example is Intervet’s Compact® IPN used against infectious pancreatic necrosis virus infections of salmon in Chile.

1) Norvax® Strep Si
2) Slice* Premix
3) Fujipenin* 40 
4) Aquaflor*-L
5) Aquaflor*
6) Bicomarin* 5% Powder 
7) Isran* Soda
8) Tribrissen* 40% Powder 
9) AquaVac* ERM 
10) AquaVac* ERM Oral 
11) AquaVac* FNMPLUS
12) AquaVac* Furovac 5 
13) AquaVac* Furovac 5 Oral 
14) AquaVac* Furovac 5 Vibrio 
15) AquaVac* Vibrio 
16) AquaVac* Vibrio Oral 
17) AquaVac* Ergosan* 

Monday, October 1, 2007

Probiotic In fish Farming

Probiotics are dietary supplements containing potentially beneficial bacteria or yeast, however lactic acid bacteria (LAB) are the most common microbes used. (Wikipedia)
Term “probiotic” inevitably referred to gram-positive bacteria associated with the genus Lactobacillus. (Fuller R. A, 1989)
"live microorganisms administered in adequate amounts which confer a beneficial health effect on the host". (FAO
Are generally called the bacteria which can improve the water quality of aquaculture, and (or) inhibit the pathogens in water there by increasing production.
"Probiotics", "Probiont", "Probiotic bacteria" or "Beneficial bacteria" are the terms synonymously used for probiotic bacteria

Types of Bacteria


-Normal inhabitants of the human and animal colon.

-Normal inhabitants of the human intestine and vagina.


-Found in dairy products and is commonly responsible for the souring of milk.


-Treat diarrhea associated with antibiotic use.

-Found in milk and milk products. Used in the production of yogurt.

-A probiotic strain that has been used in the management of diarrheal illnesses.

Benefits of Probiotics

Provide additional nutrients thereby reducing feed costs.
Maintaining desired conditions within the culture environment.
Eliminate the presence of stressors like NH3, NO2, NO3.
For stability and control of microbial populations.
To maintain stable water quality parameters.
To prevent bacterial infection caused by Vibrio and other Eubacterial phatogen and Viral infection.

Yeasts (Saccharomyces cerevisiae, Candida utilis, Kluyveromyces marxianus) and yeast products improving feed attractability, supporting growth by producing vitamins, minerals, nucleic acids and by stimulation of beneficial gut flora.
Improves growth and feed conversion
Improves survival rate of aquatic species.
Reduces stress and disease susceptibility
Reduces the need for expensive drugs

Selection Criteria for Probiotics
Antagonism to pathogens – producing anti-microbial substances like organic acids, hydrogen peroxide, or siderophores.

Must have the capacity to colonize the fish by adhesion, and to produce important substances, like vitamins. –to promote the growth or to protect fish against bacterial pathogens.

The microorganisms should be viable for long periods under storage as well as field conditions.

Probiotic microorganisms have to be non-pathogenic and non-toxic in order to avoid undesirable side-effects when administered to fish. (Ali, 2000)