Crab ID please - lots of pics, may take time to load

[Dickie]

Hi,

Just to start I've not added anything new to my tank (that could house a hitch-hiker) for quite some time.

A couple of weeks ago, I found these on the bottom of my tank. The only crabs that I know of in the tank are some scarlet hermits and a mithrax. I was slightly concerned about thse as the claw looks considerably large in proportion to the carapace and I also didn't know if these were the result of moulting or from being eaten by something else.


http://mysite.freeserve.com/Tank/temp/claw_and_carapace.JPG

While looking at my tank last night, I came accross this crab. The markings on the joint of the claw look similar, but that doesn't explain the differences in colouring. This crab looks quite similar to a crab that came with my first piece of LR. Back then that crab had much smaller claws that seemed more proportionate to the crabs size and from left to right measured approx 2cm (including legs). I wasn't worried about it causing any harm so left it. Sorry I don't have any pics of it. I did have them on webshots, but they deleted the pics without telling me! /ubbthreads/images/graemlins/mad.gif As you can see from these pics, this crab is considerably larger.

http://mysite.freeserve.com/Tank/temp/scary_crab01.JPG
http://mysite.freeserve.com/Tank/temp/scary_crab02.JPG
http://mysite.freeserve.com/Tank/temp/scary_crab03.JPG
http://mysite.freeserve.com/Tank/temp/scary_crab04.JPG
http://mysite.freeserve.com/Tank/temp/scary_crab05.JPG
http://mysite.freeserve.com/Tank/temp/scary_crab06.JPG
http://mysite.freeserve.com/Tank/temp/scary_crab07.JPG
http://mysite.freeserve.com/Tank/temp/scary_crab08.JPG
http://mysite.freeserve.com/Tank/temp/scary_crab09.JPG

Does anybody know if the pics of the claw and carapace are from the same crab?
Does anybody know what type of crab this is?
Is the crab safe in the display tank? (no signs of it doing bad stuff yet)

At the moment, I've got it trapped in my seahorse/refugium tank.

[Chuck S]

From the picture you posted I would let him go in the refugium. This would be a good place for him. If you notice by his pinsers that they are flat scoop or spoon shaped on the edge. Alot of these crabs from what I have read are specialized in their feeding more towards the herbivorous ways. Thus the scoop shape of the claw designed to pull algae etc not a pointed claw designed to tear and shred. Now it is extremely hard to get an exact id on a that crab. I could look at several books I have and give a guess at the type but there are literally thousands of types. I have seen several types of crabs over the years in my reefs and always left them alone. If you are that worried just let it loose in the refugium and he will be non the less happy.

[tendar]

I would agree with Chuck on cup tips on claws generally lead to algea eaters more than meat eaters but like said if you have him out then put it in the sump and no more worries.
I have several hithicker crabs that have tearing cutting claws but they are all under about 1" and dont seem to bother anything other than steal a piece of mysis from favia's once in a while so I dont bother with them.

Your claw is not from the same crab you captured but unless you start missing stuff of snails start showing dead I wouldnt worry to much about it.