Crab ID

[JJ4417]

I put this up in the new section and got one reply before it scrolled off the first page. I figured I would ask the locals. I've checked Melev's and can't find anything close.

I've lost 3 gobies recently, two neons and a hector's, and an emerald crab. I never found the bodies of the gobies and the emerald was cracked open and stripped clean by the time I found him. So there was a mystery as to what was killing everything off.

The better half had her head wedged against the wall the other night and saw a 'tarantula-looking thing' along the back. Had to pull some rock out to get to him, but he is now sitting in a 'breeder' cup that I picked up. I'm guessing (hoping) he might be the reason. A 20g really limits my livestock options, and I would like some verification before I lose any more money on fish. My thinking is that you don't need claws as big as your body if you are eating dead things or algae.

Anyone else?

 

[funman1]

Yep, def meat hunter!!!
I don't have a name for him but those claws give it away!!!

I would not kill him though, he'd do great in a fuge..

 

[JJ4417]

My little 20g long is all live rock and a little hob carbon filter. No sump, no fuge, nada. I'm not into killing anything, even when he has cost me about 50 bucks. If someone wants him, speak up. (I live in Lincoln.) If not, I'll run down to YR and dump him there.

 

[funman1]

YGPM

 

[Matt_Wandell]

It's not a true crab. 3 pairs of walking legs=anomuran, the order that contains porcelain crabs and hermit crabs. My bet is it's a plain old porcelain crab, which is harmless. If you google images for "Petrolisthes" you'll see lots of very harmless porcelain crabs with very scary looking claws. Does it have filter feeding appendages near its mouth?

 

[JJ4417]

No idea...what does a filter feeding appendage look like? He does have very long antennea, and mostly red on the bottom.

 

[funman1]

Here she is in her new home..

 

[philter4]

It's an atlantic porcelin crab (Petrosisthes sp.- there are many species that are very hard to seperate), common, reef safe scavenger/filter feeder. The claws are big, but have very little strength. males have bigger claws so maybe for display or show, not sure, but they are peaceful when you find them they are in lg groups, nocternal and don't seem to bother even small fish or motile inverts. They come in on florida/caribbean live rock, they can be exposed to air for long periods if gills stay moist.

 

[funman1]

hmm well he's going to have a wonderful life in my fuge than from now on..


How big will he get?
He's about the size of a nickel right now.

 

[Matt_Wandell]

<a href=showthread.php?s=&postid=11250508#post11250508 target=_blank>Originally posted</a> by JJ4417
No idea...what does a filter feeding appendage look like? He does have very long antennea, and mostly red on the bottom.

See the two things near the mouth that look like feather dusters? They are highly adapted arms used for grabbing small planktonic prey. They wave them in the water when feeding. If you've ever seen a barnacle feed it's very similar. This is a Neopetrolisthes sp.

 

[Matt_Wandell]

<a href=showthread.php?s=&postid=11252025#post11252025 target=_blank>Originally posted</a> by philter4
It's an atlantic porcelin crab (Petrosisthes sp.- there are many species that are very hard to seperate), common, reef safe scavenger/filter feeder. The claws are big, but have very little strength. males have bigger claws so maybe for display or show, not sure, but they are peaceful when you find them they are in lg groups, nocternal and don't seem to bother even small fish or motile inverts. They come in on florida/caribbean live rock, they can be exposed to air for long periods if gills stay moist.

+1.

We have a very similar looking temperate water porcelain crab on the CA coast. They do not bother anything in captivity.

You made a typo--it's PetroListhes.

 

[JJ4417]

Never saw anything like that on him. I gave him to Steve either way. I'm running out of reasons for losing gobies. One less thing I have to wonder about. I'm sure he'll be just fine in Steve's fuge.

 

[airinhere]

That is one cool looking crab. Ever find a home for it? I would love to have it.

 

[JJ4417]

Steve (funman1) took him for me. Now I just have to get the courage to put another small goby in and see if it survives.