For anyone browsing this thread that is a bit old...
You should understand that catfish in general are opportunistic scavengers, and plecos are specialized grazers of wood and plant/algae matter. They do NOT eat fish waste, but scavenge what is not used by other fish. For the best results, avoid the temptation to overfeed your fish. They will be healthier, and the water will stay cleaner. Whatever you feed them now, give them 1/3. I promise, they wont die of starvation.