Hello there...I have one red tailed shark in my 55 gallon community tank. For awhile, he was doing well...but for the past week Ive noticed he is skinny and his color doesnt look good. I dont really understand why, he comes out of the hideouts when its feeding time. I feed flakes, wafers, carnivore frozen mixture( brine shrimp, misis shrimp, bloodworms). Ive tested my water and its good! Ive been doing regular water changes like always, once a week. Im concernd about him, but dont know what is going on. I dont have any aggressive fish in the tank, all friendlys. His fins look good, no rips or tears or anything. Please help! Thank you!