Diet related anemia in channel catfish: Case history and laboratory induction

Severe anemia among fingerling to adult channel catfish (Ictalurus punctatus) and blue catfish (Ictalurus furcatus) was reported by 39 of 166 catfish farmers in west‐central Alabama in 1983. The hematocrits of moribund fish in ponds ranged from 0 to 5%. Weekly mortalities as high as 5% in individual ponds were recorded. The gills of affected fish were pale or white, the kidneys and spleen were pink, and the liver was gray to tan. In 27 of 29 ponds where the type or brand of feed was changed, deaths ceased within 1 week. However, the disease was noted among fish regardless of the major brand or type of feed used. Under laboratory conditions, the feeding of diets from affected farms induced anemia in fry, but not in subadults. The cause of the anemia was associated with an unidentified factor or factors in diets.