Yes, you can put fish in with YBS either as their food source or as tank mates. If you want to keep the fish as pets as well (or use them as additional tank cleaners), choose fish that are small and fast and can easily escape predation by your turtles. You can also opt for larger fishes but steer clear from large predatory fish like bass, large African cichlids, and large catfish as these will attempt to eat your turtle. As a rule, turtles must be larger than the fishes’ heads. Keep in mind that fishes will require higher quality water with the proper water chemistry levels to thrive. Turtles are a bit more tolerant, so with fishes, you will have to pay more attention to keeping the water in your tank cleaner. Yellow-bellied sliders will do well in the water conditions appropriate for most freshwater pet fishes.