My common pleco who is quite large and in a 125 gl tank has sunken belly not very active kind of just floats at the top almost listless,not eating meanwhile more delicate fish like geos, peruvian angels, and green phantoms and peckoltias are all hungry and healthy. What do you think may be the problem? These commons are tough fish. I am moving him to a 40 gl with some smaller Royals so he can be the boss of that tank. I may just get him a tank of his own. He is my first pleco and was a rescue so I am very attached to him.:dk: