Biological treatment of broad bean hulls by Pleurotus ostreatus and evaluation it through tilapia fingerlings (Oreochromis niloticus) feeding. The biological treatment show increased CP, NFE and GE content of broad been hulls comparing with the untreated as well as EE and CF decreased 27 and 43%, respectively. DM and OM content decreased with 3.5-1%, respectively. This bio-converted biomass was used as non-conventional feedstuff in diets of Nile tilapia fingerlings. The growth parameters recorded the highest values with nutrition of fish fed diet (3) containing (50%) biodegraded broad bean hulls. The growth parameters also, recorded lowest values with nutrition of fish fed diet (5) containing (100%) bio-degraded broad bean hulls. The same trend found on FCR, PER and PPV% for diet (3) comparing with the other fed diets. It was observed that, the fish fed diet containing bio-degraded broad bean hulls at level (100%) gave the lowest value comparing with the other treatments. Results showed no change in body composition content of Nile tilapia at the beginning and the end of the experimental for all the experimental diets.