He's got a bacterial infection. Lower the water temp and treat with Furan. Where'd you get him? Recently lost a Texas the same way (after successfully treating for the same thing)...
Lower the temp? How much lower? I'm at 80 right now. I've had this fish for about 6-7 months and I got him from a hobbiest. Hes been fine. He's breathing heavy and hanging out by my sponge filter so im scared he'll die soon.
Did some research it appears to be duck lips. Some say raise temps and some say don't. I'm going to set it at 76 degrees. People say don't use metro in the tank it's bad and this and that. I don't want to lose this guy he's a monster 10 inch Texas