The objective of evaluate growth, enzyme activity, metabolic responses, and hematological parameters in pacamã catfish (Lophiosilurus alexandri). Four diets with different levels of substitution of the cornmeal (CM) by guava meal (GV) ― 0, 33, 66, and 100% ― were tested and the feeding rate was 6% of the total body weight. A total of 160 experimental fish with an average initial weight of 16.29 g were distributed in 16 aquaria and fed for 45 days. Growth, metabolic, and hematological parameters, and digestive enzyme activity were evaluated at the end of the experiment. The level of substitution of 100% of the growth parameters were affected by the substitution of CM by GM. No effect was recorded in survival (P