found this hitchhiker tonight in a hole in a rock. It is a small (1/2") orange crab with black tipped claws (center of pic uploaded). I was able to catch him and have him separated but assume he will misbehave in a reef? Can anyone ID and tell me what he is and how he would behave in a reef? Thanks so much.

Steve, there are commensal crabs that can fit this decription.

Can you get another piccy now that he's out?

Here is another pic. I am thinking of giving him to a friend with a FOWLR tank. Would he be okay there? CarmieJo does commensal mean this could be in a reef without issues? thanks for all your wisdom. Steve

Well.. it's not a swimming crab. The back legs give that away. So, it's probably not going to go actively fishing for tankmates. BUT... that claw sure looks like it means business. Funny, the black tip reminds me of a stone crab (can you tell I'm hungry).

It looks like Atergatis, a red reef crab but they get big! Xanthidae?

I thought stone crab too lol!

I wouldnt risk letting him stay in your reef.

Steve,

Commensal organisms derive food or other benefits from a host without helping or harming it. REEFWONDERS.NET - Dive Travel Reports (http://www.reefwonders.net/encyclopaedia/com.asp?sezione=6&enc=4)

gave him to a friend with a FOWLR tank and will see how he does there. Thanks all for your help. Steve

looks like a cool crab, but i would not take the chance either. looks kinda like a porcelain crab to me, but i am no expert on crabs. keep the jokes to yourselves !!

Porcelain crabs are easy to ID. Their first set of chelae are huge, but I've not seen them black tipped. They are used for battling with others of their species and not for hunting fish, coral or other "tank thangs" :) though they can and will use them for scavenging bits of larger fare from the substrate when the feel the need.

What is "tell tale" about them is the "walking legs". From the pictures above, I can't get a good view, but they have 3 sets, rather than 4 in other crab species.

Another "give away" is the set of long "setae" located near the mouth. These appendages look like improvised fishing nets and move to and fro sifting the water for smaller (plankton like) fare. Put some cyclopeeze or BBS in the tank and if you see this "seining" action with feather like hands, you've got a porcelain crab.

They are neat crabs, harmless to your system and inhabitants, if in fact, that is what you have. If you can't ID it as a porcelain crab, I'd still be afraid of that guy.

Dave

wow ... i dont see how you have any room left in that brain ?? lol

i can barely remember all of the corals i have and what they require, much less everything you have tucked away for a rainy day !!

Again, I'm a first class nerd... I really, really wanted to go to Woods Hole Oceanographic Institute.. who knew my dad would get cancer, and I'd work on a farm to pay a mortgage as a teenager.... ah well.. it is what it is...

Again, I'm a first class nerd... I really, really wanted to go to Woods Hole Oceanographic Institute.. who knew my dad would get cancer, and I'd work on a farm to pay a mortgage as a teenager.... ah well.. it is what it is...

Sorry to hear that. I happen to have a good friend who was at Woods Hole for undergrad, then to Scripps for grad. Used to visit him at school from time to time. Did a lot of work with Ctenophore and Urchins if I remember. You probably would have a lot to talk about...

What's worse, is I have a Summer home in Falmouth...and visit Woods Hole often. Ah well... I can't complain. I've got my health and Talkingreef :)

Dave

I can't complain. I've got my health and Talkingreef :)


And we appreciate having you! :thumbs:
I've learned so much from this site!

What's worse, is I have a Summer home in Falmouth...and visit Woods Hole often. Ah well... I can't complain. I've got my health and Talkingreef :)

I just remembered. I was visiting the same friend at Woods Hole one Summer weekend, and we were walking along the shore when we saw the water teeming with Ctenophore. We waded out to our waists and had hundreds of Ctenophore displaying their luminescence. He described several theories on how they feed (which at the time was not all too known), and was able to show me their basic anatomy.

Very cool. Probably the coolest thing I've seen around that area.

They are very cool. At my favorite fishing spot, as the sun goes down and the tide goes out, they literally sweep right by my feet, flashing and glowing as they are dragged back out of the inlet by the outgoing tide. Kewl site!

D