I love this little ecosystem I have in this enclosure. No, it's not an old tub...it's a high-tech, complicated...thing. It's like a bog. I have water hyacinth, duck weed and floating marshpennywort. It's full of crayfish, breeding snails and mosquito fish. I toss in dead minnows from my stock tank here an now for the crayfish, but for the most part everything takes care of itself. The mosquito fish eat the mosquito larvae, the snails eat them as well, munch on some of the algae and take care of the dead plants and the crayfish take care of ...everything. I do overflow the tub, I mean high-tech holding thing, here and now, but other than that nothing. I feed the snails to the turtles as well as the crayfish. And the mosquito fish keep the mosquito larvae in check in the ponds.