A lot of times if they eat to much, and this can go for fish too, they will simply throw the food back up. But like the others said above, watch for him being lathargic or acting odd in any way. If his behavior has not changed significanly then he should be fine. Also your feeding schedule of 3 times a week should be sufficient, but if he does start to get aggressive towards your other fish you may want to throw in a snack here and there to keep him happy.