Suitable fish for AB

[sphelps]

I believe 3 feet is the recommended minimum to prevent all the water from freezing solid. However I think most stick to 2 feet because anything deeper qualifies as a pool and would require a railing by code. Plus it's safer for kids and such if you keep it 2 feet or less. You prevent it from freezing with a deicer or something along those lines. As for other fish, no idea but I've only really seen people winter koi outside, met others with a large variety of other species but they bring them indoors for the winter.