Treat these fish with suspected «velvet disease» with chloroquine. Velvet disease a parasitic dinoflagellate infection by Piscinoodinium spp. in freshwater fish and Amyloodinium spp. in saltwater species.
The Tx in ornamental fish is typically chloroquine or copper sulfate (provided alkalinity is > 50 mg/L), given as a bath or in a quarantine tank. The Tx in fish raised for food in the U.S. is repeated Txs of copper sulfate (assuming alkalinity is > 50 mg/L) (similar to Ich, Ichthyophthirius multifiliis) or hypersalinity.
«Velvet disease» is one of the biggest health concerns in captive marine fish, especially clownfish, and can look like white spots. The nonmotile trophont (feeding) stage of this parasite attaches to the skin and gills.
After feeding, the trophont gives rise to the reproductive stage (tomont) which encysts and forms hundreds (up to 256!) flagellated, free-swimming stages (dinospores) that go on to initiate new infections. This exponential reproduction makes the prognosis guarded if Dz is not caught and Tx early.
Potassium permanganate is one Tx for oomycete infections in fish (primarily fresh-water), along with hypersalinity and formalin. Clinical presentation includes gray-white, cotton-like growths on the skin, eyes, gills, or fins.
Tricaine methanesulfonate (MS222, Syncaine®, tricaine mesylate) is the only anesthetic licensed in the United States and Canada for food fish intended for human consumption.
Image courtesy of My digital life.
