UPDATE; after bumping up his water temperature he seems to move around a bit more. He's also been basking more. So he will go bask, jump back in for a swim, and then goes back up to bask again after a while. Is this a good sign? Could it be possible that he didn't like the previous water...
So for some background info, "he's" fairly young (almost 2 months old) and we're just worried about him and want him to be happy and healthy.
We adopted him towards the end of August, and the day we brought him home he seemed quite inquisitive and energic and he ate all of his food...