FISH HEALTH MANAGEMENT 317 



Figure 88. Ichtyobodo (Costia) infection on a rainbow trout (blue slime disease). 

 (Courtesy G. L. Hoffman, Fish Farming Experimental Station, Stuttgart, 

 Arkansas.) 



several days, depending upon temperature, each adult may produce up to 

 1,000 ciliated tomites. The tomites burst from the cysts and must find a 

 fish host within about 24 hours or die. Upon contact with the fish, the 

 tomites penetrate the skin and begin to feed and grow into adults. At op- 

 timal temperatures of 70 to 75°F, the life cycle may take as few as 3 to 4 

 days. The cycle requires 2 weeks at 60°F, more than 5 weeks at 50°F, and 

 months at lower temperatures. 



Ich is known as "salt and pepper" and "white spot" disease by aquarists 

 because of the gray-white specks that appear on the skin. However, on 

 some species of warmwater fish, mainly the golden shiner, Ich is found al- 

 most exclusively on the gills. On rare occasions, Ich infections on catfish 

 also may be restricted to the gills. In severe outbreaks, losses may precede 



Figure 89. Severe Ichthyopthirius infection (white spots) in the skin of an Ameri- 

 can eel. (Courtesy National Fish Health Laboratory, Leetown, West Virginia.) 



