I went out herping the other day. I saw a bullfrog or green frog swim away and figured I wasn't going to have any luck. Anyways, I went to go collect some cattails that were growing and saw a tadpole. I saw a bunch more, and I decided to take home a total of 7. They're about a centimeter long and are black. I've determined that they're either Fowler's toad, American toad, or spring peeper tadpoles. I've heard mostly American toads, so I think that's what they most likely are. I can figure out filtration myself, but what size tank should I get for these guys? I really need to know because the container they're currently in is getting dirty and I don't want to waste money on a filter that won't work for a larger tank. Thanks!