I have a fairly established tank~3 years old. Noticed a couple of oddities the other day on my live rock. The first looks like a spiders egg sac about 1/4" round. Its off white with a hole in the center. Next there looks to be an anemone about 1/2" round. Next I added a hermit crab the other day but don't know the exact species. He is about 2" long. Thanks for any help.