Crab ID please...?

[fishbait]

Hello,

This morning we were watching our cleaner shrimp molt and all of a sudden the two clowns and a bi-color dottyback started attacking him and bit off his eyes and now he's dead!!

Anyways, due to our closely watching the tank we noticed a little red crab (see pic) that is about 1 cm across running around in the tank. I can guarantee you we never put him in here, so I guess he was in the rock or something before we got it. We captured him for the time being - can any of you recognize this little guy, and better yet - do you know if he is beneficial or harmful for a reef system? I figured if we put him back in we may never see him again so we should find out first if he's good for the tank.

Please note the pic is close up - the crab is only 1 cm across.

Thanks

[Saber]

I have had only two experiences with unwanted crabs, neither of them good. First one grew to over 5 cm before I ripped everything out of the tank to get him. In the mean time two cocoworms and several other tube worms disappeared, never to be seen again. I Just took a small crab out of my nano that was not invited as well. I knew something was up as every morning I would find some of my smaller corals face down in the sand bed. After a few weeks, I found one of my corals torn up pretty bad. This crab was only about 2 cm across. To me, not worth the risk, as identification is at times almost impossible as there are thousands of species that can be found in the tank, and I would suggest most are not beneficial. I thought about building a small tank, three or four gallons, just to put these little buggers in. Maintenance would be very minimal, but haven't got there yet

[Der_Iron_Chef]

What corals do you have? Is it possible it hitchhiked in on a colony of SPS coral? Acropora or Pocillopora? Are its pinchers disproportionately larger than its body?

[christyf5]

I'd get him out of there pronto. He doesn't look like any type of "symbiotic crab" to me. The textured shell and red eyes usually tell the tale. I vote harmful (maybe not now but eventually, especially when he grows bigger). Either put him in your sump or get rid of him somehow.

[fishbait]

I think the forum has spoken!!! I think we'll throw this little dude in our sump, see how he fares. It won't be too hard to pull the rock out of our sump if we need to get him later, but I don't relish the thought of tearing apart the whole tank to find him later!!

Thanks guys.

[KrazyKuch]

Toss him in the toilet....I had one that looked very similar to him.....he got to be about the size of a toonie before he ate 2 of my fish in 2 days.....I put him in the sump and he tried climbing into one of my pumps were he got stuck so I pried him out and put him in the far side of the sump before all the baffles...He climbed through all the baffles and tried to get in the pump again, were he got ripped to shreds and almost took the pump with him!!

[christyf5]

Originally Posted by KrazyKuch

Toss him in the toilet....I had one that looked very similar to him.....he got to be about the size of a toonie before he ate 2 of my fish in 2 days.....I put him in the sump and he tried climbing into one of my pumps were he got stuck so I pried him out and put him in the far side of the sump before all the baffles...He climbed through all the baffles and tried to get in the pump again, were he got ripped to shreds and almost took the pump with him!!

Ooh good call, never thought about him getting caught up in the pumps. I had a hermit crab bust up one of my impellers once I have guards on my pumps now so I don't have to worry about that happening again (knock on wood, those hermit crabs are determined).