Hitchhiker Crab ID Help!!

[Owens187]

just wondering if anyone can id this crab for me, so i know if it is bad or not. i caught it last night , it came in on some aquacultured fiji live rock. i have it in a separate container till i know what it is. the pics arent that great, so maybe you can post a pic of what you think it might be, so i can compare them to it. it is kind of silver/ gray colored with black bands on its legs. the right claw is bigger than the left, with both claws very pointed. the legs are very hairy, and the claws and body have some hair also. the fifth pair of legs is not reduced. any help would be greatly appreciated!!

[Germanman]

hard to tell cause the photos are blury but looks hamles probally a sponge carb or one that eats coral mucus

[Pineapple]

I need to see the Carapace and claws. It is a true pain to ID crabs but fun to do. If you have a reef I wouldn’t take the chance. Some crabs if big can eat your fish.

It may be in the family Xanthidae by your description.

[GeorgiaMan]

With the discription of the hair, i would be concerned that it could be a Gorilla Crab. If so, it is a bad crab because it will eat your fish while they are sleeping when it is bigger. I had one that hitchhiked in on some live rock. I had to remove him. If you see hair on the legs back, I would not risk it.

[Crown Royal]

Crabs, as a rule, are all opportunistic feeders.

Better to err on the side of caution if you are not sure what it is exactly.

[Owens187]

heres a few more pics, maybe theyll help. for some reason i cant get my camera to take clear pictures up close, even though it has a macro setting. i dont know what im doing wrong, as i see all of your guys up close pics so clear. i want to find out if its safe or not so i can get the extra container out of my tank! lol :help:

[Dangerdoll]

I've always heard that if the crab has hair, it's not a good guy for the tank......

[Pineapple]

I still can’t tell. The picture is not close enough and blurred. Judging the out line of the claws it may not be bad for the health of your fish. Hair on a crab is for protection. It hides them amongst algae. Usually they live among the rocks.

Here is a picture of a crab to avoid for fish. Notice the claws. Ignore the color, or pretend it’s black and white.

http://www.jamarc.go.jp/zukan/c/c-1/c-m035/c-157.jpg

http://www.jamarc.go.jp/zukan/c/c-1/c-m036/c-161.jpg

Look at these crabs. If I didn’t have a reef I would get either one.

http://www.edge-of-reef.com/brachiuri/BRApilumnus0339.jpg

This one is in someone’s reef. What a brave soulhttp://www.mjc70.co.uk/images/teddy_t.jpg

[Owens187]

the claws on this one are just like your first and second picture, really sharp, and the right being bigger than the left. i cant see the claws in the third, but that looks pretty dam close to this one. what is that one??

[BadRoma1]

emerald crabs have hair on their legs, but they are not too bad. i have a big one of those and my baby clown fish are still alive. by the way, anybody knows how big emerald crab gets? do they always grow? your crab looks like emeralt to me, but i haven't seen too many crabs in my life.

[Dangerdoll]

I wouldn't trust it. It has too many characteristics for a bad guy...

[BadRoma1]

i forgot to say that emerald crab claws are rounded at the tip.

[Pineapple]

http://www.jamarc.go.jp/zukan/c/c-1/c-m036/c-161.htm

The common name is hairy crab, Family Pilumnidae.

The crab you have may be a mithrax.

[Pineapple]

I don’t know what gorilla grabs are but it may be the Australian species Pilumnus fissifrons.

[GeorgiaMan]

Here is information I found on Gorilla Crabs, hope it helps.

You want to keep a lookout for Gorilla crabs (xanthid species). These pesky buggers are predators that can cause damage to your reef, eating anemones, clams, and anything else they can get their claws around. They might look cute when they're small, but it's just not worth putting them into the tank. If you really want to keep them, you could put them into your sump/fuge (if you have one).

The sure-fire way to spot one of these is to look for the black tips on their claws. As they get larger, they become quite "hairy" all over. Take a look at the catalog of organisms for pictures of other "good crabs" that may hitchhike on your rock.

[Owens187]

im thinking it is a gorilla crab. thats the only one that looks like this guy. the tips of the claws are very pointed and black, so im thinkin bad-guy.

[GeorgiaMan]

agreed. I had one just like it. Was all excited at first because he was a freeby with the live rock, then I was not so excited when I determined what he was.
Sorry

[Owens187]

yup.....chitty.....but i do have a 2 gallon tank i used to have a betta in, all ill need to get is a small heater and i can keep him in there. any ideas of anything else i can keep with him in there??

[Pineapple]

Badroma1,

The Mithrax sculptus reaches the size 2 ½ inches.

[Pineapple]

These crabs can get big 400 mm or 16 inches. He will need a large aquarium. If it is in Xanthidae.

[Germanman]

from your clearer picture i think it is an emerald mithrax crab (mithrax sculptus). i sell them at my work as good hair and bubble algae eaters, and i have one in my reef tank. they only get 2-2.5 in and from A pocket guide to Marine Invertebrates."A relatively safe herbivore, but there have been occasional reports of it attacking sessile(stationary) animals." but because your pics are so unclear i would seek id from a petstore or experenced friend in your town.

[Pineapple]

Anything with black claws is a gorilla, or is it all Xanthidae?

I forgot the other species of crab. I wanted to see if you could see the difference between the two. Here is the definition of carapace, sorry if you already knew. Crabs are my favorite to ID. Thanks for the mind tease. See you on other posts.:)

http://www.jamarc.go.jp/zukan/c/c-1/c-m035/c-157.htm

http://en.wikipedia.org/wiki/Carapace

[Owens187]

i dont think it is a emerald, as all the emeralds ive seen are green(hence the name), and have smooth claws. this guy is silver/gray with hair all over.

[Pineapple]

If it is in the family Xanthidae don’t feed it to your fish. This family has poison much like a puffer. It may be bad for the fish’s health if consumed. I look at so many, and I should’ve not posted that. You forget things when you learn about a lot more subjects.

Look at the carapace of this family, Xanthidae. This site may help you ID.
http://www.poppe-images.com/images/search_results.php?category=Crabs&family=XANTHIDAE&byfam=ok

I really have to go. I’m taking over this thread. Good luck on trying to find your species. If you can get a better picture, I’ll take over again. :)

[Owens187]

well i have bought a small heater, and now have it in the two gallon tank.....im thinking maybe a marine betta to go with it?? i just could not bring myself to kill it(almost positive it is a gorilla) ill post pics of it in new setup soon! from our link itlooks like Eriphia verrucosa....thats the closest yet!!

[mysis]

Well, i definately would not trust ANY true crab in a reef tank, they will eventually destroy something, even emeralds (my friend had a sea apple and it nipped the feeder tentacles), luckly we were there to watch it and he pulled it out straight away.

[Pineapple]

That may be a Pilumnus, Family Pilumnidae. They stay relatively small. The hairy crab that was in someone’s reef tank is a Pilumnus vespertilio, size 1.6 inches, and a mud crab.

I would not put a crab in a reef. Some people have success. It’s like my coral beauties. People will say reef safe, while others say they’re terrors.


This is what Pilumnus look like.
http://www.marlin.ac.uk/baski/image_viewer.asp?images=Pilhir&topic=Species