i'm a bn breeder, so i have 7 breeders, thousends of fry, and usually around 200 juviniles. in that size tank you could easily fit a couple juviniles, but they would have to be re-homed when they got bigger then 2 inches. maybe a small school of tetras, and 2 juviniles... but if you don't have any tanks that you could rehome them, you probably couldn't fit anything else.