Crab Hitch hiker, good or evil

Well I got this today on a piece of rock. I saw it on the rock, and this looked like a molt. When I got it home, I noticed it was still alive. Very transperent/white.

I couldn't get him to pose, so I have the shot from the back. I have no idea what kind he is, maybe albino and how big or destructive he will get? And the diet. This thing total width is less than an inch.

He will be in a glass jar, I am not too fond of crabs unless it is going to leave my other critters corals pylops mushroom sponges alone.

Any advice appreciated.

Thanks

Hey Jes, I found a picture of a larger looking but I don't see how this tiny thing could become this thing on the beach, but the color is correct. Would an emerald crab be albino?


http://ooto.info/photos/storage/1000.8.84.FH000008.JPG

Cool then, When I knocked him off the rock (in the tank already) he moved rather fast through the water. I saw some swimming crabs but not the colors. I just searched emerald crabs and did not see any youngsters.

I would much easer take a risk if my tank life was more established, but I have what looks like coral starting, pylops starting and some other stuff that could not withstand much predator action.

Also bear in mind this is a picture from the back looking forward.

Oh I just found a pic that is close, Acro Crab. Sounds like I can keep him.

http://www.wetwebmedia.com/acrocompfaqs.htm

It appears I have two of them. another one is inside the coral? I saw his claws sticking out after lights out. Then I saw the first one over on the rocks where I put him back.

Anybody have some names for them?

When I thought I only had one, I was going to name it "grins" :worthy: because of how much she (you if you're reading grins) loves the critters. :naughty:

But now that there are two, that changes it.

What is the life expectancy of an acro crab?(if that's what they are) Will they reproduce? I have had a hard time finding good info on these little crabs.

This is what these crabs hang out on. The second one is encased within this and can only see one claw and an eye, the first one was clinging to the outside.

I have no idea what this is, I forget, as I was really not that interested in this. It just came attatced to the live rock which was "attached" to the urchin I wanted. I just really wanted the urchin for cleaning tasks ( and he is doing it well) and figured the rock looked nice, and the thing on top I would give a shot at growing. (not the crabs)

So anyway, best I can tell, the crab and it's host like eachother.

This thing is mostly white, the flashlight just makes it look more not white.