help ID this crab

[roscoe]

I just found this crab. Is it reef safe?

 

[burning2nd]

looks safe 2 me... small claws

is that a emerald?

 

[roscoe]

I don't know it was a hitch hiker.

 

[CarlaW]

If it was me, I sure would not throw it back in the display, just to be safe. I don't think it is an emerald.

 

[firefishred]

yes its safe, Its an emerald crab! I have two of them. They help to control my caulerpa/grapes algae.I have never seen them nip or eat any of my coral! I have had them for awhile.

 

[surf_buddy]

If it was me, I sure would not throw it back in the display, just to be safe. I don't think it is an emerald.

I have one exactly like that and it's been tearing appart my softies. As soon as I catch him he's being banished to the fuge, or he might make a good sacrafice to the porcelan gods... Oh yeah it also steals food from my LPS... after its been completly ingested. He just sticks his claw in the mouth of the polyp as far as it can go, and steals food. Watch its behavior closely before making any decisions. I have my mind made up.

 

[MikeS]

yes its safe, Its an emerald crab! I have two of them. They help to control my caulerpa/grapes algae.I have never seen them nip or eat any of my coral! I have had them for awhile.

First, there are many species of crabs that are nearly identical in physical appearance to emerald crabs. Second, almost all crabs, emerald crabs included, are basically oppritunistic omnivores, meaning if there isn't enough of their prefered meal, they may just move on to the next easiest food supply, which could be some of your coral polyps. Or they may go straight for the goodies and skip the algae altogether, I've seen it happen. Claw size isn't a good indicator of temperment/dietary habits either. All claw size will tell you is that, well, the crab has small claws. IMO, when dealing with an unknown crab, you are much better off to err on the side of caution and put him in your fuge or something like that, don't return him to the display tank.

MikeS

 

[idhound]

we have 2 of similar type haven't had many problems with ours they are different colors from each other white one wears mushroom for a hat he hides under it, other is purple stripped they were hitchhikers

 

[roscoe]

Yeah I have him in a container in the tank. I'm deciding what to do to it.

 

[idhound]

we have both in our main tank and love watching them, the white one looks just like yours and he is under the mushrooms i think he is in the emerald family or anemone crab from what i can find have had the purple one for almost a year the white/green one for about 6 months no problems yet they will once on while take food out of carpet anemone, carpet is about 18 inches across if the mated clowns don't run him off

 

[firefishred]

The best thing to do is listen to the RC Staff !! Because they NO Best!! Right ??

 

[matts125]

First, there are many species of crabs that are nearly identical in physical appearance to emerald crabs. Second, almost all crabs, emerald crabs included, are basically oppritunistic omnivores, meaning if there isn't enough of their prefered meal, they may just move on to the next easiest food supply, which could be some of your coral polyps. Or they may go straight for the goodies and skip the algae altogether, I've seen it happen. Claw size isn't a good indicator of temperment/dietary habits either. All claw size will tell you is that, well, the crab has small claws. IMO, when dealing with an unknown crab, you are much better off to err on the side of caution and put him in your fuge or something like that, don't return him to the display tank.

MikeS

Couldnt have said it better!!!

No crabs in my reef (EVER) I have caught them eating softies to lps and beyond! Very oppurtunistic indeed

 

[csdoyle]

I've had Emerald crabs tear apart my mushroom corals quite viciously.. They were a pain to catch, but I was glad once they were gone.

Chris

 

[MikeS]

The best thing to do is listen to the RC Staff !! Because they NO Best!! Right ??

The fact that I'm staff here doesn't make me somebody that "NO's best"...I do however have 20+ years experience in marine tank keeping, and my reef will be 8 years old this year. That doesn't necessarily make my information correct either. My statement is based on both my research on the subject and my personal observations made during my time in the hobby. I invite everybody to do thier own research and draw their own conclusions, I don't expect anybody to blindly follow anything I say just becasue I'm a staff member here or I have a lot of time and experience in the hobby. Remember, when two people argee all the time on everything, that usually means only one of them is doing the thinking...

MikeS