Keep temperature ACCURATELY at 75 degrees, if you are not already doing so. Do one large water change up to 25% more than you normally do, and up to 80% of entire tank. Then just leave him. The more you move him or try to (force) feed him, the more stress you will impose. Let him go a few days feeding only during mid day (once a day) nothing more than 2 or 3 pellets at a time. It will take him up to a month to come around. PM me for more details.