Royals eat veggies, driftwood, algea, and some meatier treats such as brine shrimp or worms. They require a slight bit of protien, but not a lot. They do absolutely require driftwood, and will litterally eat it in large quantities. They won't eat you other fish, hover they are mildly territorial with any fish ( will go after any fish that enters their territory, but won't persue them far), and vicously territorial with other pleco's. The biggest royal I have seen was 12", I see the 15" claims on occasion, and think it is probably possible, but 12" seems to be the more common claim. Bear in mind that a 12" royal will be roughly 5 inches wide accross the body. So even if they don't get the 15" length, they are a massive animal when fully grown. Mine particularly loves cucumber and green beans, but eats pretty much anything I put on the veggie clip.
Dave
