I wish I had room for three big tanks.
Anyways, an update. Right before I went to bed, I did a water change of about 30% and put some of my filter media from the big tank in to float in the qt. He looked pretty happy so I went to sleep after watching him eat a few Hikari Cichlid Gold pellets.
Woke up about half an hour ago to splashing. Ran and turned on the lights and he was jumping like crazy, and he didn't stop even though I was watching him, so I knew something was wrong. I dumped him in the 55 right away, figuring if he had anything contagious the coppersafe I put in there a few days ago to get rid of some hydra had a good chance of taking care of it.
He sank to the bottom when I put him into the big tank and laid on his side for a few minutes. Then, he righted himself, rested a minute or so, and started to slowly explore the tank. I didn't have time to get the 30 ready for my pair of small angels, but he's chilling with them right now, happy as a clam. The angelfish didn't seem to want him around at first, but he's been persistent in following them, so they gave up on trying to ditch him. I've been watching them for about 20 minutes and there's been no aggression, but I'm afraid that may change when I turn my back.
I tested the water in his tub and no2 was about .3 or .4

ph was 8, which is about 20x more alkaline than it comes out here. It's usually right at 6.8 to 7 (could the plastic container contribute to this? PH has never changed that drastically that quickly before) and ammonia was 0, I have to pick up something for nitrates so I didn't test those yet. I was really careful about picking the container and I made sure I cleaned it well with very hot water before we put him in, but I'm sure there could have been something other than the tub at work here.
Dang, he's more trouble than I had anticipated, but I'm glad he recovered so quickly.