Nazzy has a point... if its being grazed on, that could explain the small peripheral tentacles. Especially if its larger, as the shrimp tend to avoid those until they get really hungry.
Yes, I have two peppermint shrimp in this tank, but the anemone hasn't changed appearance (other than size) since adding the shrimp and it's been in the tank longer. It's looking more and more like a strangely colored aiptasia, but it isn't propigating at all so... I dunno.
Also, the peppermint shrimp love the Prime Reef flake I feed to the wrasse; they aren't going hungry for lack of regular aiptasia in the tank.
There are many kinds of aiptasia... so you may be seeing just another type. I have one, that has been in the tank for 3 years. Hasn't seemed to spread at all. Gets huge (3" long) and just sits there. I have tried a dozen times to knock it down with kalk, hot water, acid, nothing seems to work, but it doesn't spread either. And... the shrimp pretty much ignores it.
That's the assumption I'm going on now. I'll watch it to make sure it doesn't start spreading. This tank will be MUCH easier to keep aiptasia under control than my 150 anyway, so I probably stressed way too much over this to begin with. :lol: