"Emerald" crab hanging out on birds nest

[Sean Duggan]

Hi everyone earlier this week I picked up two emerald crabs from my LFS to deal with some bubble algae. I added them in and saw them throughout the week periodically on the live rock picking at stuff. Well yesterday and today both of them have been in my birds nest colony. It's a decent size colony about six inches across and 4 inches tall. I thought it was odd that both of them were just hanging out in there. It is a pretty big tank 5 feet long and 130 gallons. Is it possible I got some type of coral or acro crab? I've been watching them pretty closely, as I know people have reported them going rouge, and I see no damage tp the birds nest. Just thought it was kind of weird that both of them would be hanging out in it, in such a big tank. Just wanted to know if anyone else has ever experienced this.

 

[Sean Duggan]

tried to get a decent photo of them.