Acriflavine, a historical antiseptic compound used in topical treatments, has a longstanding application in fish treatment. It is recognized for its effectiveness against bacterial infections, parasites, and fungi like flavobacterium, fin rot, velvet, Cryptocaryon irritans, Hexamita, Ichthyophthirius multifiliis, Saproglenia sp., Ambiphyra, Chilodonella, and Oodinium. Its antiseptic and antifungal properties are particularly useful in disinfecting fish eggs.

Acriflavine can be administered as a short-term bath for individual fish or introduced into the water to treat entire systems or ponds through prolonged immersion baths.