A study was carried out to evaluate the dietary effects of phytase on African catfish (Clarias gariepinus) fed fishmeal-free diet. A fishmeal-free basal diet (40 % crude protein, 6.5 % lipid ) was formulated and supplemented with graded levels of phytase (0, 0.25, 0.5, 0.75 or 1 g kg -1 ). The catfish (2.5 g fish-1 initial weight , 20 fish 30 L-1 stocking density) were fed either of the diets twice daily. After 8 weeks of feeding, all the catfish fed phytase ( at 0.25, 0.5, 0.75 and 1 g kg -1 levels of inclusion) supplemented diets had significantly higher final body weight (g fish-1) , mean weight gain (g fish-1) , percentage weight gain (%), specific growth rate (% day-1), protein efficiency ratio and improved feed conversion ratio (P < 0.05). There was no significant difference observed in the condition factor, viscerosomatic index, hepatosomatic index and survival (%) of the catfish fed the test diets (P > 0.05 ). However, the whole-body composition of the catfish fed the test diets differ based on the level of phytase supplementation. The whole-body crude protein content was highest in the fish fed 0.75 g kg-1 phytase supplemented diet and lowest in those fed 1.00 g kg-1 phytase supplemented diet (P < 0.05) . The whole-body lipid content was highest in the fish fed 1.00 g kg-1 phytase supplemented diet and lowest in fish fed 0.00 g kg-1 phytase supplemented diet (P < 0.05). The whole-body ash content was highest in the fish fed 0.25 and 0.50 g kg-1 phytase supplemented diets and lowest in those fed 0.00 g kg-1 phytase supplemented diet (P < 0.05 ). The histological examination of mid-intestine of the catfish fed the test diets revealed intact epithelial barriers with extensive mucosal folds into the lumen. The perimeter ratio of the catfish mid-intestine was however not significantly different after 8 weeks of feeding the test diets (P > 0.05). Samples are still being analysed to further established the effects of phytase supplementation on digestibility, uptake and release of nutrients (phosphorus inclusive) by the African catfish when fed phytase supplemented fishmeal-free diet. From results obtained so far, it can be concluded that African catfish (C. gariepinus) had improved growth performance without negative effect on somatic indices and survival when fed phytase supplemented fishmeal-free diet.