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.