Hitchhiker Crab ID

[PSH]

Good or bad? Pretty cool looking IMO.
http://img.photobucket.com/albums/v669/PonderosaSnakeHouse/Saltwater/PICT1739.jpg

[Amphibious]

He's very cool. It looks like a shame-face crab because of their ability to hide behind their pinchers. Don't know the scientific name.

Potentially, it can capture fish at night and eat them. I had two fish disappear a couple of months ago. No carcass, nothing on the floor, just gone. About $50 a piece. Then I noticed a crab that I didn't put in there. I was lucky he made a mistake and was in a top rock that I could simply lift out and got him out of there. He's different than yours but yours could pose a problem. Here's a pic of mine.....

http://www.theculturedreef.com/KillerCrab.jpg

Not big but lethal. Mine is now in a perforated container in my sump waiting for a new home. Can't bring myself to just kill it. He doesn't deserve to die just for doing what is natural to him.

[JustDavidP]

Can you get him out for a good pick like Dick shows? Shame faced are not the best choice for a busy tank, but yours looks like it may also be a different crab. It may just be a beautiful Porcelain Crab. Again, a better image would help. Otherwise, read below....

Porcelain crabs should be easy to identify if you google images. They have three sets of walking legs rather than four (See the 4 sets in Dick's image?). The fourth are tucked away under their carapace.

If you get the chance to see it in the tank, watch to see if it is "seining" for food using large feather like setae located near their mouth. They literally comb the water as it passed by and eat smallish particulate matter, to include detritus. Mine also take cyclopeze and smallish meaty foods.

Porcelain crabs have what look to be MIGHTY MEAT EATING and dangerous claws. Showy, not vital for feeding but for fighting (they actually will drop one or more claws -hence the name "porcelain"- if dealing with the "Fight or Flight" issues..thought to give them increased mobility in retreat).

Porcelain crabs are often found as hitch hikers because they like to hide in the various nooks and crannies of LR and come out pretty much only when feeding.

Dave

[PSH]

It's not a porcelain crab I have one of those in my nano. There several of these crabs in my 75. This one is the most colorful. They always seem to be picking at the rocks when I do see them. This one is about the size of a nickel. They don't seem to bother anything right now so I will let them be.

[JustDavidP]

Correct... a porcelain crab would not be picking at rock.

D

[BrianPlankis]

Correct... a porcelain crab would not be picking at rock.
D

Usually true, but I have had two species of porcelain crab in my tank and both of them would use their filter feeding appendages to scrap the rock. They didn't use their claws to scrap the rocks, but they were more or less picking at the rock and seemed to be trying to gather up detritus to filter through.

Brian

[JustDavidP]

Brian,

I've seen that as well. It is as if they are stirring up the detritus and such. Actually, my seahorses will do the same. They almost lay down on the sand and rock and use their pectoral fin to "fan" the rock and sand and disturb food so that it is visible and in the water column.

Dave