Mudcatfish (Heterobranchus longifilis) juveniles (body weight 61.60-83.05g, length 204.43 ~c 3.07 - 229.53 ~c 3.65mm) were fed with diet containing crude protein (CP) levels of 30%,35% and 40% for 10 weeks, using fishmeal as a protein source. Growth performance and feed utilization were investigated. Fish were raised in plastic aquaria of dimension 46 x 38 x 28cm3 at a temperature range of 26.0-29.0~'C, pH value of 6.6-7.4 and dissolved oxygen of 3.5-5.1 mg/1. The highest increase in body weight (23.30 ~c 4.30g) and specific growth rate (0.68 ~c 0.02% day-1) were achieved with Diet 2 (35%CP). The condition factor ranged 0.60 ~c 0.009- 0.66 ~c 0.005 and fish survival was 100% for all diets. Protein efficiency ratio (2.37 ~c 0.35) was also significantly better with 35% CP (p<0.001). Diets 1(30% CP) and 2 (40% CP) gave lower performances. The observations in this study suggest that a 35% high quality protein diet will probably provide the needed protein requirement for H.longifilis juveniles
