I have 8 small tads that I think are probably spring peepers. We collected a few eggs from a local pond. They hatched about a month or so ago and were doing quite well. They seem to be growing normally. I have been keeping them in a container with about 2-3 inches of water in it. I change about 1/2 of the water every two days with week old tap and feed them a small pinch of flake fish food daily or a few of those tadpole pellets crushed up. Recently, I noticed that a couple of the tads are hanging at the top of the water belly up. Their bellies seem to be bloated and full of bubbles. I have seen them blowing bubbles out of their mouths. The water seems to quickly get a ring of bubbles around the edge of the container. What is wrong and what do I need to do to keep them alive?