On many occasions in recent years -- since commercial catfish culture has become an important endeavor -- fish disease personnel at Auburn University and at other research and diagnostic laboratories have examined catfish which showed disease symptoms without signs of disease-causing organisms. The fish usually showed one or more of the following characteristics: crooked, humped or even broken backs; white (depigmented) vertical band across the back; irregular surface swimming; tetany when handled; poor growth and mortality. Fish pathologists have referred to this condition as the "crooked or broken back syndrome." Fish showing this condition usually came from a culture environment where natural aquatic food is limited -- such as cages, raceways or ponds which had a higher poundage of fish than is generally found in conventional pond culture. Examination of the history of the fish revealed that they were intensively fed feeds that did not contain supplemental vitamin C. These symptoms have not been observed in catfish with access to a significant amount of vitamin-rich pond organisms or when feeds containing supplemental vitamin C were fed.