Well, I should have probably clarified a little. We got him at about 3 pm, put him in the new tank and immediately left for a cookout. Came back to a dark house and flicked on the lights and went right over to him. That's when I noticed the bubbles everywhere and that he wasn't really moving.
But a little later, with just a little light on, I peeked in at him and he was swimming all around. So maybe I just scared him?
I did some reading on here and found that they make bubble nests, but the bubbles are everywhere, on the sides, the bottom, the rocks, and floating on the top.
I guess I'll have to see if he's still alive tomorrow morning...