What kind of crab is this?

[cheryl]

We purchased a sherbert sponge today and when we placed it in the tank there was a little crab on it. It's about 1/2 in size and greenish in color. It sat for a few minutes rubbing it's front claws together then went and started eating alge. It actually pushed the sponge back about a 1/4 of an inch because we placed the sponge very close to the crab (not having seen it until we put it in the tank!). Not a great description but can anyone help?
Thanks

 

[ak_reefer]

It may be an Emerald Crab. Take a look at the picture that swf.com has. Just click on swf.com and click on crabs and you will see Emerald crab they have a picture there. HTH

 

[whipple]

I agree sounds like an emerald crab, good to have great algea eater and shouldnt harm anything in your tank.

 

[cheryl]

Thanks for the information. Upon further inspection it does look like an emerald crab.(he/she finally came out of under the sponge). The picture on SWF was not that great, but now that the crab has come out and started to climb the live rock, we can see that he looks like the SWF picture. Active little critter!
SHould we eventually get more or are we limited to one?

 

[heavenly damsel]

I have three in a 55 gal tank...couldn't swear too it but I think I saw two of them mating the other night...will let everyone know if we have babies! They get along fine and do a great job cleaning up the bottom of the tank. They love flaked food when it makes it to the bottom. Fun to watch too.