Hitchhiker in new tank

[seabeedoc12]

I just got my tank running 2 days ago and put in rocks collected on the beach. I thought that would be safe, but I already see a brown hairy thing hiding in a hole that ate a shrimp piece. Guess its a gorilla crab. Also, there is this white mucous-stuff growing on one of the fresher rocks. I tried to take some photos. Should I get these rocks out?

 

[bethnjeremy]

did you actually collect them on the beach? If you didn't thoroughly clean them, get them out. If I were you I would go out further and collect rock. Then I would take them home and clean them by scrubbing them and then bake them for a while. Baking it will get aiptasia's which can spread throughout your tank quick and if you have color they can sting them.