Mystery Crab

[Molino]

I got some LR for my tank just a week ago. With the LR I also got a tiny stow away! I spotted him the first night while looking at my LR. I was not able to find him again until today and he was out long enough for me to snap a few pictures, one of which is in reasonable focus. He is very tiny, maybe a half inch in width including his legs.

Does anybody know what type of Crab this is? And where I could find some information on him, size, etc..

Thanks

 

[charlesr1958]

Looks like a cling crab to me, which while small seem to do no harm other than scraping the rocks for food, larger specimens can be problamatic as their size increases, so does their capability to cause damage/losses. I normaly do not allow any of the free ranging crab species in my tank, being omnivoures, it is usualy only a matter of time before they figure out that there are meatier items to add to the menu. I have some details about cling crabs ID features HERE

Chuck

 

[The steven liu]

That crab does not look reef safe at all, I cannot pin point the species but from the build of the body and the eye I can tell it is a predator not a scavanger.

 

[Molino]

Thanks. Any tips on how to trap them? I have discovered now that there are at least three... I have heard putting a small piece of shrimp out in the open, or in a glass to allow the crab to get in, but not out. Any other suggestions?

If I know which piece of LR the crab is in can I remove that from the tank and run it under fast running freshwater to try and flush the crab out? Or will that damage other organisms/bacteria in the LR. Or will soaking in FW for several hours cause the crab to attempt an escape?

I'm also debating trying to set up a 10 gallon to put these guys in if I can trap them. If they grow larger than 1-2" it'd be interesting to keep them.

Thanks again.

 

[charlesr1958]

If you can remove the rock, that is the best option, since you can then squirt very hot fresh water into their holes using a large syringe, taking care that only the hole gets a dose of water, Seltzer water will flush them out as well. Either way, do not soak the rock in any other type of water. If all else fails, I have used a piece of metal coat hanger to ruin their day very quickly. This is a good example of why its a good idea to quarantine rocks as well, besides helping to prevent Ich transmissions, it gives you time to watch for unwanted critters before they become part of the main tank's landscape.

Chuck

 

[Molino]

Thanks for your help Chuck,

This is a brand new tank, so not much reason to quarantine and should make it easier to rid myself of these pests