I have a 180g saltwater tank. I bought it 6 weeks ago. It was already a 3 year established tank. So far everything survived the moved. As well as a few new editions. We have three clowns, 2 blue damsels, 2 black damsels, 2 white striped damsels, 1 yellow tang, 1 mandarin dragonet, 1 lawnmower blenny, 1 chocolate chip starfish, 1 conch, 4 turbo snails, several hermits, 1 peppermint shrimp and two blood shrimp. Everyone gets along. Water levels are spot on. Tonight I was looking for my dragonet and noticed what looks like a smooth, round, white ball attached to a rock. None of the fish seem to be "protecting" it or attacking it. Can anyone please help identify it?