Common plecos tend to be oppertunity feeders. He's enhancing the protien in his diet with a little tubiflex, no worries. Mine take everything from fresh zuchini to raw shrimp down. Keep in mind, common plecos are "bulk" eaters. Even if he's getting enough nutrients from algae wafers and lettuce, he might not feel full. In nature, these fish consume large amounts of detrius every day. Supplimenting him with a little parboiled zuchini might help him feel a little fuller, but he's still going to nibble your tubiflex cubes sometimes. And your koi pellets, and your flake food, and your shrimp pellets, and your cichild floaters and anything else he can get his suckermouth on. These fish like to eat!
