Is this crab reef safe? Just found about 3 hitchhikers tonight
 

Does anyone know whether these crabs are reef safe or whether they will eat fish? This is the first time I've seen them because I used a flashlight to check out what was goin on in my tank at night.

[IMG]http://reefcentral.com/gallery/data/500/58692DSC00258.JPG[/IMG]

Looks like an emerald crab to me, completely reef safe; eats bubble algae.

I don't think it's a emerald crab. I would have to see the claw and the picture is too small to tell. I had one that just look like that one, red eyes, sharp claws. Emerald crabs have long claws and the tips are flat. If that one has fat and short claws with sharp tooth, then take him out.

[QUOTE][i]Originally posted by SeanCallan [/i]
[B]Looks like an emerald crab to me, completely reef safe; eats bubble algae. [/B][/QUOTE]
It'll eat bubble algae if you are lucky.
Mine don;t do squat.
I suspect mine is munching on coraline....:mad2:

I have one of those as well, sharp claws and red eyes...
So far mine has left everything alone in my tank with the exception of 2 new chromis I added a few weeks ago, they lasted 3 days and just disapeared without a trace. Both at the same time. My little crab is about the size of a half dollar.

Ya, it's tough to tell in the photo for sure but it looks like an emerald. If so you have no worries.

Trust none of these IDs. Impossible to ID from that pic. Most hitch hiking crabs are pests. In fact, most crabs period are not reef safe. Get rid of it now.

I had a crab that looked like that one in my tank that hitch hiked on some zoanthid live rock that I had bought about 3 months or so ago. Since then, I lost 2 peppermint and 1 skunk cleaner shrimp. I caught the little bastard 2 days ago, and needless to say, he's no longer in my tank. Now I will restock those shrimp I lost. I would get it out if I were you.

Looks like a normal rock crab tro me. Scavenger, but an opportunistic feeder too. If it does not have enough to scavenge upon, it may try to catch a fish or eat some worms and stuff.

I completely agree with mickyfin. Crabs are extremely hard to ID even with a great picture, much less one that doesn't show many identifying characteristics like this one. However I can say with a fair amount of confidence that this crab isn't even in the same family as emerald crabs. I would get rid of him as almost all crabs are opportunistic (ie. they will eat whatever is easiest for them to get be it live, dead, prepared, or frozen) and can become a problem if their preferred food isn't available.

Agree with the aboves.

Even you have a good picture it is still not easy to id, many of them just look too similar. But it doesn't matter, whatever is the species, some are safer, some less safe, but none is completely safe. I de-crab my liverock when I buy them, but I knew there is still one in my reef that I can't catch.

definitely not an emerald (mithrax)....claws are too pointy and also the shape of the body is disimilar, more likely a memeber of Xanthiidae family...definitley should be removed...

Thanks guys, it definetely isn't an emerald crab since I know what they look like.

This one is reddish black, with red eyes and has big claws for a crab that size. The one in the pic is about the size of a nickel, but if they're harmful to my small fish or other crustaceans, I'll try to catch the little bastard.

Can someone please confirm this? If so, I'll have to do some serious crabtrapping tonight. :(

I stole this pic from wetwebmedia, but this is what it looks like:

[IMG]http://www.wetwebmedia.com/Arthropoda/CrustaceanPIX/SWCrabs/crabid_WWM.jpg[/IMG]

[IMG]http://www.wetwebmedia.com/Arthropoda/CrustaceanPIX/SWCrabs/Mystery_Crab_Flash_2.jpg[/IMG]

I am getting mixed reviews from their website, but I was wondering if anyone has any personal experiences or suggestions on these little guys.

Thanks alot

I have. I found that they were eating my nassarius snails. I don't know what it would have eaten when those ran out. I used a small trap to get them out.

You can tell they are predatory by looking at the claws.

I had several just like those, came from Indo-Pacific rock. I've heard them referred to as "Gorilla Crabs", but lots of crabs get tagged with that alias.

Definately get rid of it, mine decimated a nice patch of zoos, killed a 20 dollar shrimp and stalked my sleeping clownfish stressing him to no end.

I took some small delight in freezing him solid.

It's definitely not an Emererald.
You should get rid of it because it looks like it's closely related to [url=http://archive.reefcentral.com/forums/showthread.php?s=&threadid=386290&highlight=nuisance]this killer.[/URL]

Yup, that's the one I had in my tank also. Red eyes, sharp claws, very mean looking. Take him out.

Look [url=http://archive.reefcentral.com/forums/showthread.php?s=&threadid=470822]here[/URL] for more recent crab trappings. Anyone know what kind that one is?

Bad news... get it out

Agree.

[QUOTE][i]Originally posted by prop-frags [/i]
[B]Look [url=http://archive.reefcentral.com/forums/showthread.php?s=&threadid=470822]here[/URL] for more recent crab trappings. Anyone know what kind that one is? [/B][/QUOTE]

Thanks for the tip Mike, I'm gonna try that one tonight and see if it works.

Well I tried the ole crab trap last night listed above, and all I caught was a bunch of hermits! I guess I have to try again :(

Has anyone had experience with the inverted bottle trick? Or is that strictly for mantis?

Oh ya, I keep hearing the occassional clicking in my tank! I assume that would be either a mantis or a pistol shrimp. I've read a couple other threads on catching mantis and they suggest the bottle trick. Does this take a few nights of setting the trap to actually catch something?

does that crab by chance have two white lines at the top of the shell in between the eyes in this configuration: | | ? i have oone like that.

[QUOTE][i]Originally posted by kusanagiz [/i]
[B]does that crab by chance have two white lines at the top of the shell in between the eyes in this configuration: | | ? i have oone like that. [/B][/QUOTE]

Not really sure, I'll take a look tonight. Why?