Give him some time in his qt setup, he might be reacting badly to the different chemicals and medicines, and needs some time to get them out of his system. If you do suspect internal parasites, try soaking his pellets in garlic juice, it's perfectly safe for the fish and a natural parasite treatment.
I would definitely try using prime when you're ready to take him out of qt, and it can't hurt to add a little more than recommended. It definitely sounds like you have some sort of water quality issue. Maybe you could contact the water department of your city and ask about it. If the prime doesn't help, you may have to look into reverse osmosis water.
Last edited by LolaQuigs; 03-22-2011 at 10:54 AM.