What diseases affect percula clownfish?
Most percula clownfish diseases come from stress and a handful of marine parasites. Percula — sold as "true percula" — get the same marine diseases as ocellaris, but wild-caught percula arrive with more parasites. Brooklynella, the slime-producing ciliate often called "clownfish disease", was confirmed in Amphiprion percula in Blasiola's review of outbreaks, and velvet and marine ich are the other fast-moving threats.[1]
Act the same day if your percula clownfish breathes fast and shows dust, slime or peeling skin. Velvet and Brooklynella can kill within days; move the fish to a quarantine tank and start treatment.
For any other symptom, test ammonia, nitrite, salinity and temperature first — water problems cause more illness than any single parasite.
Why percula clownfish get sick
"Percula" and "true percula" are the same species, Amphiprion percula. It differs from ocellaris by thicker black edging on the white bands and usually one fewer dorsal spine (9–10 rather than 10–11).
Many percula in the trade are still wild-collected. Wild fish spend days in holding systems before sale, which is where Brooklynella and velvet spread; Blasiola lists A. percula among the anemonefish hosts of Brooklynella.
Captive-bred percula are as hardy as ocellaris. If you can choose, buy captive-bred and quarantine anyway.[1]
| Scientific name | Amphiprion percula (true percula, orange clownfish) |
|---|---|
| Adult size | Up to about 11 cm (4.3 in) |
| Temperament | Peaceful to moderately territorial |
| Usual source | Captive-bred and wild |
| Main health risk | Brooklynella has been confirmed in A. percula; wild-caught fish carry more parasites |
Percula Clownfish symptoms and what they mean
Most percula clownfish diseases first show up as one of eight symptom groups, covering the 30 signs owners describe most often. Find the closest match, check the urgency label, then confirm the likely disease in the table below.
Breathing problemsEmergency
Covers: gasping, rapid breathing, coughing
Fast gill movement, gasping at the surface or "coughing" (sudden flaring of the gills) is the most important sign on this page. Gill parasites — velvet, Brooklynella and flukes — attack the gills first, often before anything shows on the skin, and low oxygen or ammonia produce the same picture.[1][2]
Percula note: Fast breathing with clear skin in a new percula is the early, gill-only stage of Brooklynella or velvet — both start on the gills.
Spots, slime and skin lesionsUrgent
Covers: white spots, black spots, spots on fins, fuzzy growth, mucus coating, missing scales, red streaks
Distinct salt-grain dots point to marine ich; a fine gold-grey dust to velvet; thick, peeling slime to Brooklynella. Red streaks and open sores are usually bacterial or Uronema infections taking hold after an injury. Firm, white, wart-like lumps on the body or fins fit lymphocystis, a virus documented in captive clownfish.[1][2][3][4]
Percula note: Patches of white slime that look like the fish is "peeling" are the textbook Brooklynella sign in percula. Start formalin the same day.
Not eating, bloating or a sunken bellyUrgent
Covers: not eating, sunken belly, bloated
Refusing food for a day or two after a move is normal. Refusing food in an established fish is often the first sign of a parasite. A swollen belly points to overfeeding, constipation or internal infection; a pinched, sunken belly to long-term underfeeding or internal parasites.
Percula note: Wild-caught percula may not recognize pellets. Start with frozen mysis or brine shrimp enriched with vitamins, then mix in pellets.
Swimming sideways, sinking or floatingUrgent
Covers: swimming sideways, floating, sinking, curled body, darting, jumping
Losing balance — floating, sinking, swimming sideways — usually means a swim bladder problem or an advanced infection. Darting and jumping are signs of irritation (parasites) or of being chased. A curved spine that develops over weeks can be nutritional or degenerative rather than infectious.[5]
Percula note: Darting and jumping in a newly added percula often mean it is being chased; check the tank at lights-out.
Cloudy or bulging eyesUrgent
Covers: bulging eyes, cloudy eyes
One cloudy or swollen eye is usually an injury. Both eyes together suggest infection, flukes or poor water quality. Corneal cloudiness was one of the first signs of skin flukes in imported reef fish.[6]
Percula note: Percula have a naturally orange iris; only clouding of the clear cornea over the eye is a symptom.
Torn, clamped or rotting finsUrgent
Covers: fin rot, torn fins, clamped fins
Clean tears are fight damage; ragged, whitish edges that keep receding are fin rot. Fins held tight to the body (clamped) are a general stress sign — check water quality before anything else.
Percula note: Torn fins in percula usually come from a mismatched pair establishing which fish becomes female.
Hiding, lethargy, scratching or aggressionWatch
Covers: hiding, lethargic, aggressive, rubbing
Scratching on rock ("flashing") is an early parasite sign and deserves a close look under a flashlight. Hiding and lethargy are vague on their own; combine them with breathing and skin checks.[3]
Percula note: Percula can be more territorial than ocellaris, especially once paired. A fish that is chased and hides constantly needs to be separated.
Losing color or turning paleWatch
Covers: losing color, pale color
Fading is a stress response — a new tank, bullying, unstable temperature or salinity. Pale color together with excess slime and fast breathing is the classic Brooklynella picture and is an emergency.[1]
Percula note: Fading is one of the most common percula complaints. If it comes with slime or fast breathing, treat it as Brooklynella, not stress.
Common percula clownfish diseases and treatment
These are the parasites most often behind the symptoms above. The clownfish health problems guide compares them side by side with an illustration of what each looks like.
| Disease | What you see | Speed | Treatment in quarantine |
|---|---|---|---|
| Marine ichCryptocaryon irritans | White salt-grain spots, flashing, faster breathing | Days–weeks | Copper at 0.15–0.20 mg/L free copper for at least 3–6 weeks, hyposalinity, or tank transfer[3] |
| Marine velvetAmyloodinium ocellatum | Fine gold-grey dust, very rapid breathing, hanging at the surface | Can kill in days | Short freshwater dip for relief, then copper at 0.15–0.20 mg/L free copper[2][7] |
| BrooklynellaBrooklynella hostilis | Thick white slime, peeling skin, pale color, rapid breathing | Can kill in days | Formalin baths or prolonged formalin; copper did not eradicate it[1] |
| UronemaUronema spp. | Red ulcers that spread quickly, often from an injury | Days | Formalin; formalin, malachite green and hydrogen peroxide were all effective in lab trials[8] |
| Flukesmonogenean flatworms | Flashing, cloudy eyes, heavy breathing, clear skin | Weeks | Praziquantel baths — 2 mg/L given twice, four days apart, in one study[6] |
Treating a percula clownfish
Treat percula in a separate hospital tank. For Brooklynella, Blasiola reported that formalin baths or prolonged formalin immersion worked, while copper at 0.15–0.20 mg/L did not eradicate it — so do not rely on copper alone if you see thick slime.
Copper is effective against ich and velvet only while free copper stays at 0.15–0.20 mg/L, so measure it with a test kit at least daily; it is lethal to most invertebrates and must never go into a reef tank.[7] Leave the display without fish while you treat: marine ich can complete its life cycle in anything from 6 days to 11 weeks, and its guidance calls for 3–6 weeks of quarantine, sometimes 7–11.[3]
How to keep percula clownfish healthy
Most percula clownfish diseases arrive with a new fish, so quarantine every new fish for at least four weeks before it joins your percula clownfish, buy captive-bred where you can, and keep temperature and salinity steady. Feed a varied marine diet in small portions; a fish in good condition fights off parasites that would overwhelm a stressed one.
Full setup advice is in the clownfish care guide.
Percula Clownfish diseases FAQ
Is a true percula the same as a percula clownfish?
Yes. "True percula" is a trade name for Amphiprion percula, used to separate it from the ocellaris, which is sometimes sold as "false percula". The diseases and treatment are the same.
Why is my percula clownfish losing color?
Usually stress from a move, bullying or unstable water. If the fading comes with thick slime or fast breathing, it may be Brooklynella, which needs formalin treatment the same day.
Do percula clownfish get Brooklynella?
Yes. Brooklynella hostilis has been confirmed in Amphiprion percula, along with maroon and tomato clownfish, in published outbreak reports.
Research sources
- Blasiola, G. C. (1983). A review of Brooklynella parasitization in marine fishes: diagnosis, pathology and chemotherapy. IAAAM Proceedings. Read source
- Francis-Floyd, R. & Floyd, M. R. Amyloodinium ocellatum, an important parasite of cultured marine fish. Southern Regional Aquaculture Center Publication No. 4705 (2011). Read source
- Yanong, R. P. E. Cryptocaryon irritans infections (marine white spot disease) in fish. University of Florida IFAS Extension, EDIS FA164. Read source
- Cheng, et al. (2022). Lymphocystis disease virus infection in clownfish Amphiprion ocellaris and Amphiprion clarkii in Taiwan. Animals 13(1): 153. doi:10.3390/ani13010153 Read source
- IAAAM Proceedings. Case report of a non-infectious degenerative myopathy in captive-bred clownfish (Amphiprion clarkii). Read source
- Cardoso, P. H. M. et al. (2019). Neobenedenia melleni (Monogenea: Capsalidae) in ornamental reef fish imported to Brazil. Revista Brasileira de Parasitologia Veterinária 28(1). doi:10.1590/S1984-296120180076 Read source
- Yanong, R. P. E. Use of copper in marine aquaculture and aquarium systems. University of Florida IFAS Extension, EDIS FA165 (revised 2024). Read source
- Crosbie, P. B. B. & Munday, B. L. (1999). Environmental factors and chemical agents affecting the growth of the pathogenic marine ciliate Uronema nigricans. Diseases of Aquatic Organisms 36: 213–219. Read source