No clue what this could be, single polyp, 3/8" across approximately. Does not feeble any coral in the tank, closes up and opens with the lights.
I do have a small hydroid (I think) on an acan, other than that I have not seen any clear pests or hitchhikers in the tank other than some worms I had leave the tank when getting rid of Zoas.

I do have a small hydroid (I think) on an acan, other than that I have not seen any clear pests or hitchhikers in the tank other than some worms I had leave the tank when getting rid of Zoas.

