Brooklynella (Clownfish Disease)
Brooklynella hostilis
Critical severity ⚠️ Contagious
the dreaded 'clownfish disease', a fast marine protozoan that strips slime from stressed new fish
Symptoms
Catching illness early gives the best chance of recovery, so check your fish daily. Excess slime sloughing off the skin, rapid breathing, gasping, faded colour and loss of appetite, classically in newly-imported clownfish. Act promptly if you see several signs together.
Causes
A marine protozoan that spreads fast among stressed, freshly-imported fish (especially clownfish), damaging the skin and gills. The underlying trigger is almost always stress, poor water quality or a newly introduced animal.
Treatment
Treat promptly in quarantine with a formalin bath/dip and supportive care; it progresses fast, so early action is vital. Keep water pristine and reduce stress.
While treating, increase aeration, remove activated carbon from the filter, finish the full course even after symptoms fade, and keep the water immaculate. Marine treatments belong in a separate quarantine tank, never the reef.
Prevention
Quarantine and observe newly-imported marine fish - especially wild clownfish - before adding them to the display. The golden rules: quarantine new arrivals, never overstock or overfeed, avoid sudden swings, and keep up regular water changes.
FAQ
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This information is general guidance, not veterinary advice. Consult an aquatic vet for serious cases.