BTA's can have bubbletips, or not. It seems to be something they do, or not. It appears to be an unknown factor. I have two of them. Tne one in my 52G is ignored by the Ocellaris Clowns, but it has bubbletips. The one in my 20H has two Percs living in it, and has never had bubbletips. They were purchased at different times from the same place. Both get frozen krill once a week.
