Peps will be fine in the tank either way but I am curious. If they are easily removed, they are thankfully not aptasia. I have an odd little critter that looks like some kind of an egg when it is floating about but will bury in the sand and feed at night with arms spread upward. It is larger than what you are seeing though. Since they are easily removed, take one out and put it in a shallow bowl of tank water and work to get a GOOD photograph.