Zebrafish are highly susceptible to velvet disease, a parasitic dinoflagellate algae. Most fish from dealers or pet stores carry velvet disease and have the characteristic behavior of rubbing their sides and flipping around in corners of the tank. As the disease progresses, fish become lethargic; the fins (particularly the dorsal fin) are held close to the body and the fish stop producing eggs. Parasites can be seen near the fins and gills through a dissecting microscope.

Treatment for velvet disease using Atabrine (Quinacrine hydrochloride)

Day I - Slowly drip 2 quarts of sea salts into an infected 10-gallon tank. (20 tablespoons Instant Ocean in 2 quarts of system water)

Add 3.3 ml Atabrine stock solution (10 mg/ml H20)

Day 2 - Add 3.3 ml Atabrine stock solution

Day 3 - Add 3.3 ml Atabrine stock solution (for a total of 9.9 ml)

At the end of the 3-day period, clean the bottom of the tank thoroughly and slowly dilute out the salt and Atabrine with fresh water.

Continue cleaning the bottom of the tank daily for several days.