Fish pond effluent discharge into the environment is becoming a nuisance since it contains contaminants that harm the ecology and water quality. In this study, we examined the possibility of using a mushroom Lentinus squarrosulus Mont. in removing impurities from fish pond effluents before discharge into the environment. Untreated effluent was obtained from a fish farm in Eleme Local Government Area of Rivers State, Nigeria and tested for contamination levels using physicochemical and microbiological methods within 24 hours of collection. Sterilized sawdust was bagged, inoculated with mushroom spawn and given two weeks to colonization the substrate. The colonized substrate was prepared for mycofiltration after the third week. With a sterilized stainless-steel spoon, holes were drilled into the substrate's centre, and the untreated water sample was then poured into the holes and allowed to filter through into a sterile container. Filtrate samples were taken to a laboratory for evaluation. Statistical analysis of data obtained after 24–48 h of mycofiltration treatment of aquaculture effluents samples showed a substantial (P≤0.05) decrease in heterotrophic count from 6.7×10³ to 0 and total fungal/yeast count from 5.3×10³ to 0. The findings revealed that mycofiltration technique is a useful, efficient and affordable technology as it reduced dissolved oxygen from 7.92 to 2.88 mg L^-1, biological oxygen demand from 5.97 to 5.62 mg L^-1 and chemical oxygen demand from 1.89 to 1.78 mg L^-1. Other parameters such as pH, turbidity, electrical conductivity, total dissolved solid, total suspended solid, sulphate, nitrite and phosphate, and algae count were reduced significantly at the end of the filtration process. There were notable variations (P≤0.05) between values obtained from fish pond effluents and that treated with L. squarrosulus, indicating that the mushroom played a promising role in the process of mycofiltration and also showed that mycofiltration is a healthier method for water quality improvement of fish effluent before discharge.