Grey mullet (Mugil cephalus) grazes on plant detritus and microflora and is an omnivorous fish species of ecological importance in both mono- and poly-culture due to its unique feeding habit. However, little is known about the effects of different diets on the growth and body composition of M. cephalus. To address this question we carried out an 8-week feeding experiment on M. cephalus with initial weight of (25.0±1.59) g. The experimental subjects were fed with four groups of diets that were flour (T1), rice bran (T2), shrimp feed (T3) and fish feed (T4). The results showed that the specific growth rate (SGR) and the feed efficiency (FE) in T1 and T2 were significantly lower than those in T3 and T4 (P＜0.05). The SGR and FE in T3 were 1.46 %/d and 48.62% respectively which were 2-fold of those in T4. Fish fed with a single diet of either flour or rice bran barely grew in size but had higher survival rates (＞80%). The weekly average daily food intake (DFI) of T1 and T2 decreased to below 0.80 g/d after 4 weeks, whereas the weekly average DFIs of T3 and T4 were above 0.80 g/d and obviously increased in the 8th week during the experiment. The whole body crude protein was the highest in T2 (18.62%±1.36%), and crude lipid was the highest in T3 (10.52%±0.36%). There was apparent accumulation of crude lipid in T1 (8.01%±0.42%), which indicated that the higher carbohydrates (flour) level could enhance the lipid accumulation in the whole body of the fish. Moreover, the level of whole body crude protein could be well maintained when the formula feeds were replaced with rice bran. Flour or rice bran alone may not be sufficient to support the rapid growth of M. cephalus because of the lack of balanced proteins; however, they might help promote the survival rate at early rearing stage. Therefore a partial diet replacement with flour or rice bran in shrimp ponds could be a useful trial.