Mystery crab

[cookie]

Over the last few days, I have been noticing the claw of some sort of crab. I have been feeding sinking pellets the last few days in order to try and get my non-eating sand-sifter to eat and where I drop the food it where the mystery crab lives. He sticks his arm out to reach for food and this is what i can tell. He has similar claws to an emerald crab and they appear to be a very dark purple possibly black. There is a whiteish design around the joint of his claw and this is really all I can tell. i dont think he is a hermit crab as he is squeezed into a tight flat area. There is no way I can get a picture of him as he is very shy. Does anyone know what he might be or is there a good website for crabs out there? thanks!

In my tank I do have a porcelain crab and an emerald crab both of which i have had tabs on while seeing the mystery fellow.

 

[gotfish]

Something like this? If so, it's a gorilla crab.

 

[cookie]

Something like this? If so, it's a gorilla crab.

Yikes I hope its not that....could be though. What do it do to get rid of it?

 

[gotfish]

Does it go inside of a rock? I've read that you can pull the rock, hopefully it doesn't have any coral on it. Mix up a saltwater solution with the salinity at like 1.036 or so and toss the rock in it. The crab will evacuate the rock trying to get away from the water and will end up in the bucket. I've never done this so I don't know if it actually works, just read it online. May want to wait for someone else to chime in on this method.

You could also try and trap it, but that could take forever and chances are it only comes out at night.

 

[Pentagona]

Probably some sort of rock crab, get him out while you know where he lives and squish him!

 

[cookie]

A bit more info...he is defenienty very dark in color and just the tips of his claws are white. He hangs out on a rock and reaches down in the sand for stuff to eat.

 

[mfinn]

One way to catch a crab, is to get a small wide mouth jar, such as a baby food jar.
Tie a piece of shrimp to a small chunk of live rock and put it in the jar. Put the jar at the base of your live rock, at a angle, leaning against the rock. It may take a few nights, but I've caught quite a few this way.

 

[salty3]

I think it's a type of xanthid crab. I found one just like it in my tank. I left it in there and it did great for a while then all of a sudden I lost a fish and every snail. I moved it to the sump and bought more snails and haven't lost anymore. I would deffinetly remove it.

 

[BobinCovington]

I used a pint beer glass with a heavy little container of food (i.e. small pvc with net wrapped around to prevent bait floating away). Leave it overnight...crab falls in and can't get out.

 

[cookie]

I used a pint beer glass with a heavy little container of food (i.e. small pvc with net wrapped around to prevent bait floating away). Leave it overnight...crab falls in and can't get out.

what would you suggest if the rock he is leaving in is right at the sands level? He is living just barley off the sand....Thanks and great photos!

 

[BobinCovington]

He will move to get to the bait in the glass at night. Just lean it against the rock at a steep angle.

You may catch other hermit crabs or critters too.