ID needed on Mr. Evil Crab.

[StevieTdrill]

Ok, So a coworker was looing over my tank tonight and said something of the like "*** is that thing?!" I shrugged it off since I stare at this thing all day, thinking it was just something he hasn't seen yet.

I come over to the tank to find a very evil looking crab. Wow, very cool. After 11 months there is still excitment to be found. He must have come in last August when the rock came in, so that is almost a year that I haven't seen this guy. I don't think he came over from my Eclipse, but anything is possible..

My guess is some kind of Xanthid crab but confirmation would be nice. As long as he doesn't try to eat small children one day, I think we can enjoy one another. I just fed him some mysis a second ago, we are not friends as I see it.

With Flash:

Using underwaer camera case:

 

[mikchabe]

I remembered seeing this in the Modern Coral Reef Aquariums books - Red Eye Crab (Eriphia sp.). Predatory. Not good in a community tank.

 

[LeslieH]

A xanthid crab, not Eriphia. Someone once identified it for me as a species of Actaea. It's an omnivore but if it hasn't taken out anything valuable it may be content with detritus & small stuff in your tank.

These are species of Eriphia -
http://calphotos.berkeley.edu/cgi/i..._sci-Invertebrate&enlarge=0000+0000+0903+0169
http://www.nhm.org/guana/bvi-invt/bvi-surv/images/crab-i06/02035.htm

 

[StevieTdrill]

Thank you for the ID, some new information on my crab

My mechanic was in here yesterday and was looking at the tank. He said it was chomping down on some corals. So I had him point out what coral he was eating. Turns out it wasn't a coral, but coralline algae. The evil crab was mowing down on some that was growing on a lower rocks bellow my carnation coral.

What is up with that? Any ideas if I should still worry and possibly nutralize this guy?

 

[boomsticks]

That is one awesome looking crab! Do they sell them anywhere or are they just normally hitchhickers?

 

[StevieTdrill]

With the risk of some of these eating corals, and that they are rarely seen in an aquarium, I would doubt anyone would sell them. My guess is that they hitchhike normally into the aquarium off of rock.

But I have seen people selling aiptasia on ebay, so i wouldn't put it past anyone.

 

[ACBlinky]

I have the exact same type of xanthid hitchhiker in my 90g. I removed him, kept him in the sump for a while, then moved him to a small 30g reef for a few months of observation. He's incredibly shy and never takes anything other than meaty foods or fish food - doesn't touch coral, anemones, or algae.

Based on his perfect behaviour, I moved him back into the 90g where he has been a model citizen for many, many months. I named him The Beast when I first found him, though he's actually the most timid crustacean I've ever seen - hermits are tougher than this guy!

He's about twice this size now:

 

[StevieTdrill]

ACBlinky-

Thank you for the pictures, that is good to hear. Mine seems to act just like yours. I only see him a few days a week but has never touched a coral. I don't know why he was tearing up some coralline algae, but we all get bored at times and need to get some aggression out. He did mow down on some mysis last week when I bated him out, lets all hope he stays happy and doesn't choose to destroy corals!

 

[Theomi]

I have that crab in living in a rock in my 150g...
Only time i see him is when i feed the tank mysis and cyclops...
Havent harmed any thing so far, he is quite shy...

 

[romunov]

I've had a similar crab in my tank. A normal reefer would call it reef safe, but I found it munching on some small animals (which I like!) so I had to freeze it.