We have a ton of bass up here in the river, and let me tell you, IT GETS COLD! It does not freeze over all the way, but the top does. We also have catfish we can catch by the dozens, when they are babies, with a net. They are actually the whole reason I have the fish I do now lol. I put them back in the river from the tank out back cause the kid who caught them wasn't feeding them. When I fed them, I cut up a worm and put it in there and you would think there were tiny sharks in there lol. They would shake the piece back and forth, which was too funny coming from a 1 inch long baby fish!