yeah its a real catch 22. all of them have been great EXCEPT ONE, that likes to crawl right over the bridge where I have a couple choice zoas and sps, and then sprawl out spread eagle over the top of them to sunbathe for the day before it crawls back into its hole. now, they haven't killed anything or poisoned anything, but of course it ticks things off and they take a day or two to recover.Those BTAs will eventually take over the tank if you don't keep the population under control. IMO, they're basically a larger, nicer looking version of Aiptasia lol.