I recently purchased some feeder fish for my AFCs ,.seem along with them i got some snails( not by my choice but obviously some eggs were in there) . the AFCs got fatter lol and the snails are thriving .I use a canister filter and a under gravel which keeps my tank quite fresh and balanced along with regular water changes, and cleaning of the under gravel filter . My canister filter has a uv light .I also feed the frogs shrimp and some tubiflex as a treat .