The present study aimed to study the effect of incorporation of increasing levels of fermented silage made from fish by-products in diets of Nile tilapia (Oreochromis niloticus) fry. After 90 days form the experimental start, the highest average BW (27.38) was recorded for control group which fed on the basal diet and replacing of 25% or 50% of fish meal FM by fermented fish silage FFS in the diets FFS25 and FFS50 reduced the final body weight BW to 25.08 and 25.22 g but these weights did not significantly different from that fed the basal diet. The higher replacing levels of FM by FFS (75 or 100%) in the diets FFS75 and FFS100 significantly (P