Effects of water treatment by two probiotic products (PondPlus® and AquaPhoto®) and sand filtration were studied on growth performance of tilapia (Oreochromis niloticus) and pangas (Pangasianodon hypophthalmus) stocked at tilapia:pangas ratio of 5:3 in traditional earthen ponds in Bangladesh. The fish were stocked at a density of 20,000 fish ha⁻¹ and reared for 7 months. Compared to untreated ponds, treatments of probiotic products or sand filtration in earthen ponds resulted in a higher O₂ content, higher water transparency, less ammonium, and fewer cyanobacteria. Weight gain for individual tilapia was lowest in the AquaPhoto-treated ponds (177 g), while similar gains (188–194 g) occurred in the other ponds. For pangas, the lowest weight gain (627 g) was obtained in the sand filter-treated ponds, as compared to 690–797 g in the other ponds. Thus, a general positive effect from the treatments on fish growth was not observed, possibly due to a reduced content of detritus (supplementary feed for both fish species) in the treated ponds.