The present study was designed to investigate the effect of supplementation of inulin and mannan -oligosaccharides (MOS), single or combined, on the growth performance, feed utilization, fatty acid profiles, and gut morphology of Chamo strain Nile tilapia Oreochromis niloticus (L.) fry reared at sub-optimal temperature (22-23oC). Nile tilapia fry (initial weight 1.6 ± 0.074g) were fed four diets supplemented with prebiotics at 0 g of prebiotic/kg of fish feed (Diet-T1), 5 g kg-1inulin-supplemented diet (Diet-T2 ), 6 g kg-1 MOS-supplemented diet (Diet-T3), or a combination of 2.5 g kg -1 inulin and 3 g kg -1 MOS (Diet-T4 ). Each diet was randomly assigned to three aquaria and hand-fed 8% of their body weight divided into three portions daily. The results showed that Nile tilapia fed Diet-T4 had the highest final weight, weight gain and specific growth rate (SGR) than fish fed Diet-T1, Diet-T 2 and Diet-T 3 although the effect was not significant ( p > 0.05). Fish fed Diet-T4 also had the highest FCR than other feeding groups. Fish fed Diet-T4 and Diet-T3 had the highest content of polyunsaturated fatty acids (PUFAs) , especially docosahexaenoic acid (DHA; 22:6 n -3) and eicosapentaenoic acid (EPA; 20:5 n-3) than Diet-T1 and Diet-T2. Gut morphology parameters revealed significant (P < 0.05) increase in villi length (VL), villi width (VW) in fish fed Diet-T4 and Diet-T 3 and higher goblet cell number (GCN) in proximal and middle portion of intestine in fish fed Diet-T3. Overall, this study suggested that supplementing fish feed with MOS alone or in combination of with inulin improved growth performance, intestinal morphology and fillet quality of Chamo strain Nile tilapia.