I upgraded to a 75g recently and my yellow tang, blue tang, and two perculas were transfered 8 days ago. For the last three days my yellow tang quit eating, and is not very mobile. water parameters are all ok. He looks bloated like he has been eating and is pretty pale. I see no signs of ick and the other three are doing great. I have had him for a over a year now with no problems other than an ick outbreak early last year. what could be causing this, and is there anything I can do to help?