he may not clean the alage, no need to feed them, they will eat what your fish dont eat, its awesome watching them eat, as soon as i open the tank hes on his way ready to eat. i wouldnt worry about him not moving around a lot, try dropping a tiny bit of food in, he will probably go right after it. How long did you accimilate, If you just put him in, give him time to get used to his surroundings. Inverts are really sensitive to water changes, make sure he has a good accimilation, and also when you add him, dont add any of the fish stores water, and leave lights off for an hour or two, because it stresses them.