So my yellow tang has been eating fine for a while now and all of a sudden last night he was in between the rock hiding and now today he has been laying down against the back of the tank and in the sand and will swim straight against the glass. He has been eating green algae brine shrimp and has been happy and full from the looks of it before. I have a 55 gallon aquarium and the fish in this tank is 2 small clownfish, dwarf flame angelfish, christmas wrasse, diamond back goby and a watchman goby. All the fish get a long but the yellow tang will try to block the angelfish, wrasse and will also go after the goby’s. I got seaweed on the the back and he wont eat it. Not sure what to do.