Predation preference and pressure of Nile perch Labs orioticus and African catfish °arras garsepinets on tilapia, mullet, coninion carp and silver carp were evaluated. Stomach content analysts of Nile perch and catfish collected from culture ponds indicated their food habits under culture conditions. The smallest predator size found was 5.5 g and 13.0 g in Me perch and catfish, respectively. Darkness fish was found to have simulating effect on the predatory process. Predation piessuie and pref­erence was determined from the information collected on the colour, weight and morphometric relationship between predator and prey. Fry recovered from control ponds were greater than those in ponds stocked with catfish. The morphometric data in regard to predation activities in­cluding length of intestine and buccal diniesions were obtained, A cone method was used which interpreted the buccal gape dimensions better.