I have a 20 gallon long freshwater planted aquarium with gravel substrate, a few rocks, large piece of wood, and an emperor 400 for filtration. My fish include 8 platies (they multiplied), 1 baloon molly, 8 tetras, a lot of cherry shrimp, 4 amanos, 4 african dwarf frogs, and a few dwarf crayfish, thinking of adding a vampire crab and a small dry zone for it.