I would ask larry if berghia would be preyed upon by your fish, they may be small enough not to be a treat. He told me he put a few in his tank and some in his fuge, they reproduced and his aiptasia went by by...
I plan on stocking up on some in a couple months, I have kalk pasted myself to death, and even with perfect water quality the little buggers just keep coming back. I have one, I have injected joes juice in right down it's throat, twice it even puffed up from the load, and it is still there, It is a miracle of nature I guess, I have no concievable idea on how it survived.
"Maybe in order to understand mankind, we have to look at the word itself: "Mankind". Basically, it's made up of two separate words - "mank" and "ind". What do these words mean ? It's a mystery, and that's why so is mankind." ~ Jack Handey