Hi Ali:

You have to follow sterile microbiological procedure as for any other animal, looking for the main organ tissue to seed in specific culture media.

The culture media would depend on the bacteria you are suspecting and the fish specie.

You can find some specific answer in many fish disease general book or some fish laboratory handbooks.

Greetings,

Patricia

First of all you need to know which pathogenic bacteria you have to isolate and from which organ of the fish the bacteria will be isolated.

Take some parts of fish organ (s) infected by bacteria, dilute with autoclaved distilled water shake at 150 rpm electrically. After serial dilution plate 200 μl on generalized or specific Nutrient media and incubate at 37 °C for 24 hrs.