Crab ID ??

[OneFishTwoFish]

I found this little crab (about a 1/4 of an inch) climbing a small Acropora today. It has fuzzy legs. It appeared to be feeding off whatever is on the Acropora, but did not seem to be causing any damage. I think it's a tiny Emerald Crab. There are 3 much larger Emerald Crabs (approx 1 inch) in my DT. Do they breed in captivity ? If I'm correct, an Emerald Crab is 'reef safe' and won't eat Acropora.

I'm looking for confirmation, or to be pointed in the right direction.

Thank You !

 

[DaveK]

Offhand it looks like a gorilla crab. Remove it. You can keep in in your sump if you like. They will eat just about anything they can catch. It's not so much the crab's fault, it's just how they are.

 

[OneFishTwoFish]

Thanks Dave !
To the sump he goes . . .

 

[Oxylebius]

It is a Cymo andreossyi, an acro crab.

Acro crabs are considered a coral symbionts. The caveat is that such symbiosis are a trade off between the coral and the crab, the coral gains protection and house cleaning services while giving up a few polyps, mucus and captured/settled food particles in exchange for those services.

Most of the Trapezia and Tetralia acro crabs cause little harm. The Cymo is a species you need to watch closely.

A healthy, large coral should have no problem repairing or replacing lost polyps, but again, in an aquarium environment, an eye should be kept on the coral for excessive damage being done due to the coral being unable to recover as fast or faster than the damage being done by the crab.

In short, its a judgement call that you will have to make.

http://species-identification.org/species.php?species_group=crabs_of_japan&id=1180

 

[OneFishTwoFish]

Thanks Oxy !
He's already been moved to my "crab zone" - a special area in my sump where 9 hermits and 1 emerald live. They have it pretty good there with rocks to explore and twice-weekly feedings.


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