Hi sorry for bad photo but saw this guy after lights out. Is pinkish with black claw tips. I have a mixed reef tank not sure how he got in but he did. Is he good or bad? I have a feeling bad and that's why some zoa's are missing their crowns : (
In general, pointy claws bad. Black tipped claws bad. Hairy or fuzzy exoskeleton with black tips bad. Gorilla crab/stone crab. Very common hitcher in gulf rock. I relocate all mine to my next gumbo.