The shrimp could be hiding out in your rock. I have sworn mine were gone, only to see them swaying upside down in rocky caves and coming out to take bits of fish when I fed the tank.Those aiptasia are a royal PITA. I have purchased 6 peppermint shrimp and they all have disappeared overnight. I have been using Aiptasia X to try and control it, but they keep popping up. I wish I new why the peppermint shrimp disappear.
Yup, definitely a tunicate. Feeding phytoplankton and bacteria products will help it survive. It won't harm anything, and for me, very desirable.
Not unusual ime. They hide well and are active at night mostlyUnbelievable. Last night around 11:00 p.m. I was looking at the my tank with the red light and I actually saw one of the peppermint shrimp. I thought all six I put in there disappeared. Then it went into hiding. I wonder if the other 5 are sill in there?