I recently ordered a pair of ORA's 'Picasso' breed of percula clownfish that arrived heavily infested with Brooklynellosis. 

After a week in the quarantine tank and lots of medication, I was able to fully cure my clownfish, with no losses!  However, this experience caused me to question “how often does the average hobbyist see this disease?  Will they be able to identify and treat it quickly enough to prevent mortality?”  I wanted to write a short (and hopefully informative!) piece about Brooklynellosis.  Because Brooklynellosis can kill very fast, quick diagnosis and treatment is essential.   


The causes of Brooklynellosis

What is Brooklynellosis, you ask?  Brooklynellosis is a protozoan parasite that commonly affects wild caught clownfish, or captive bred clownfish that were irresponsibly exposed to wild caught clownfish (as was the case with my fish).  Brooklynellosis symptoms include excessive mucous production, white "fuzz" or "rashes" on the skin.  Infected fish will also show a rapid respiration rate and act listless. 

Brooklynellosis symptoms include excessive mucous production and white “fuzz” or “rashes” on the skin. Infected fish will also show an increased respiration rate and tend to act listlessly.

Treatment
Once you've diagnosed Brooklynellosis, prompt treatment is essential.  Move the affected fish(es) to a quarantine tank, and begin treatment with formalin.  I used Quick Cure (a combination of formalin and malachite green sold to treat ich and crypt, and available at almost every pet store) at standard marine dose as directed.  Because my clownfish were also at a higher risk for secondary bacterial infection due to their weakened immune system, I added Methylene blue and erythromycin (also both sold at almost any pet store) to combat possible bacterial infections.  Finally, I dosed Seachem's StressGuard at a double dose per day to help reduce stress and replace the fish’s slime coat.  My clownfish were lucky enough to make a full recovery after 5 days, and showed great improvement after only 24 hours.

I also dosed the tank with StressGuard from Seachem at twice the normal dose per day. I consider StressGuard to be an excellent product. My clownfish showed great improvement after only 24 hours, and after five days were fully recovered.

Great success has been had with the captive breeding of clownfish, so Brooklynellosis isn't very common, and should never be seen in captive bred fish.  However, Brooklynellosis is much more prevalent in wild caught fish or captive bred fish that have been kept with those from the wild, so it's good to know what to look for.  Once you know the signs and symptoms, you will be able to identify and treat Brooklynellosis rapidly, greatly increasing your fish’s chances of a successful recovery.