My guppies are in a raft system. The plants' roots hang in the same water as the fishes. (Don't tell it can't because my plants are growing much better than the other since I started growing them like that!)
What I wanted to know is: When the roots start to become longer, can they still live in that bin?
I've had guppies in my raft system for years. Didn't set out to have them, they came in with some wild-caught fish. Never caused a problem, except that when I have to drain a trough I don't like to kill them, yet they're a pain to catch. I've had huge taro roots with very large root masses in these troughs, also tomatoes with big root systems, and as long as the trough isn't absolutely choked the fish do fine.