I had a 30 gallon fowlr at work that did have a few coral in its beginning. Mostly just gsp and pulsing zenia. I recently set up a 90 gallon and transfered the rock and sand to start the cycle. Nothing new has been added to any of my tanks in 2 years. Today I noticed two of these on two different rocks. They are about ¼" around. I've seen then all retracted in a ball, normal like the picture and what looks like tentacles extended before the lights come on. Thought?
