Saw this at local fish store and part of me wants to set up a separate quarantine tank just to see what they would do. They look just like other aiptasia (of which there were many in this tank), but these showed green luminescence. Anyone seen these before?
I have some of them. It's pretty much what it seems. They stay pretty small, about the size of a dime at most. And yeah, they spread like aiptasia too.