I had one that went from fist-sized to nearly a foot across when fully inflated in about a year - he was a monster! I fed him regularly, and he took anything from silversides to shrimp, even flakes and pellets. He even stung, killed, and attempted to eat a medium-sized cleaner shrimp that walked across his bubbles. I'm a fan of feeding LPS corals - they have large mouths and eager feeding responses for a reason.