Intensive aquaculture recirculating systems produce effluents (dissolved and particulate solids) with concentrations of nitrogen and phosphorus, a potential source of pollution if they are not properly treated. The sludge and nutrient removal by anaerobic digestion has become an alternative for aquaculture sludge digestion and stabilization. In this study we determine the effect of four different pretreatments (alkaline, mechanical, thermal and biological) in sludge reduction and denitrification efficiency, biogas production and nitrogen and phosphorus dynamics from a hyper-intensive Nile tilapia (Oreochromis niloticus, Linnaeus, 1758) culture in 15 days experiments, one per month for one year. After application of pretreatments in aquaculture sludge, an increase in the release of total ammonia nitrogen was obtained with respect to the control, in the same way nitrate removal was obtained in all pretreatments (>90%), The increase in total suspended solids removal was higher in pretreatment (>20.3%) compared to control (14.6%), As well as the biogas production increase, being the biological pre-treatment where the highest concentration was obtained (45.18 cm(3) L-1) The results indicate thatthe application of pre-treatments in the aquaculture effluents improves the denitrification processes and anaerobic digestion and can reduce the hydraulic retention time.