Improved stability and anaerobic digestion (AD) process in a packed bed bioreactor can be achieved if bacterial consortia are retained in the process through the use of biofilms carriers. Three methanogenic biofilms carriers for biomass retention were studied to evaluate the performance of methanogenesis AD of Nile Perch fish solid wastes pre-treated by bacterial culture coded (CBR-11). The carrier material evaluated consisted of sisal fibre waste, pumice stones and Nile perch fish scales. Process performance was investigated by increasing the organic loading rate (OLR) step-wise. The best results were obtained from the bioreactor packed with Nile perch fish scales. It had the lowest total volatile fat acids (TVFA) accumulated at OLR in the range of 1-12 g volatile solids (VS)/l/d. The degradation pattern showed that the TVFAs was limiting at higher OLRs. The pH profiles showed an increasing pattern with an increase in OLRs. The pH was low (8-8.3) at low OLRs (1-6) gVS/l/d and increased to a higher level (8.3-8.7) at higher OLR (9-12) gVS/l/d. Despite the high pH level reached, the bioreactor packed with fish scales had a good ability to withstand the changes in load and VFA concentrations shocks that can occur in packed bed anaerobic bioreactors. In conclusion Nile perch fish scales was demonstrated to be potential novel biofilms carrier that would work well in methanogenic biofilms bioreactors treating fish solid waste. Moreover, Nile perch solid fish wastes and fish scales are available within the vicinity, which could make AD scale-up at fish processing industry feasible and cost effective