A study was conducted to examine the use of corn distillers’ by-products in diets and the effects of additional dietary fat on channel catfish, Ictalurus punctatus, performance. Juvenile channel catfish (initial weight: 12.6 g per fish) were stocked in flow-through aquaria and fed one of six practical diets for 9 weeks. Fish fed the control + fat diet consumed more diet and had higher feed efficiency ratio (FER) than fish fed the control diet, but weight gain was not significantly different between fish fed these two diets. Fish fed the diet containing 300 g kg−1 distillers dried grains with solubles (DDGS) consumed more diet and gained more weight, but had similar FER compared with fish fed the control + fat diet. The diet containing 200 g kg−1 high-protein distillers grains (HPDDG) resulted in similar diet consumption, weight gain and FER as the control + fat diet. Fish fed the diet containing 100 g kg−1 distillers solubles (DS) consumed more diet, but had similar weight gain and FER compared with fish fed the 300 g kg−1 DDGS diet. The presence of distillers solubles in the diet (300 g kg−1 DDGS, 100 g kg−1 DS, 100 g kg−1 EDS diets) appears to increase diet consumption, weight gain, and FER over the control diets with or without additional fat.