first off saying everything is good gives no one anything to go on to help, thats why so many views and no answers. The BSU main food is Coraline, depending on your tank size and the amount you have, he may not be getting enough to eat. I have a 125 and have had a BSU for 10 years. About every 2-3 weeks I put him in the sump and let him clean it out, I also wait till he is near the top of the tank and give him Nori. Outside of that you need to offer much more information on your set what for people to help, tank size, inhabitants, parameters, type of water, history ect. If you are using tap, thats the problem, as the can not handle any type of copper, they also can not tolerate nitrates