Angels can be sensitive as the op stated.. It is possible, but wouldnt make much sense if he was eating before. Do you know what the difference in PH and KH your tank water is from the source tank water?
Not eating is usually the first sign something isnt right. I would venture to say it culd be stress from the move, hes coming down with something, he may not like what you are feeding him, he may not be hungry. How are the others acting, are they all in the 29 g?
My thoughts if they are all in the 29 g turn to a spike in water parameters. Adding 4 large fish at the same time throws a lot of bioload in a tank that even an established tank takes a few days to accomadate. What are your readings?
Blue