Crab question

[itsamyheff]

We purchased several emerald crabs about a year ago to combat an algae issue. Fast forward to recent, we have had some smaller fish disappear. We physically saw this crab grab our smaller tang(he got away but). He's more white in color instead of the normal green. Is he a emerald? He's been removed from the tank. We're just curious at this point as to what he actually is?

 

[RadiatedReef]

I’ve had an emerald crab that was red/the reddish color they look once they’ve been cooked. It’s a rare trait, but still an emerald.

The crabs are opportunistic predators, so if they are hungry enough and capable enough, it’s very possible they got ahold of a fish or two.

 

[ichthyoid]

That may be a Gorilla crab Larry. They are similar to Emeralds and sometimes mistaken for one. In any event, I agree with the hunger statement above. Crabs are opportunistic.

Gorilla Crab: A Clawed Hitchhiker | FantaSEA Aquariums

When introducing live rock in your aquarium, it's possible to get more than you bargained for. One of the uninvited visitors that can show up in your tank is the gorilla crab, a destructive and hard-to-catch hitchhiker.

www.fantaseaaquariums.com

fwiw,
I have read that some species of Gorilla crabs may be toxic?

Xanthidae - Wikipedia

en.m.wikipedia.org

 

[york1]

Aint no emerald/mithrax crab. I would sump it or flush it

 

[chuck]

dang George lol

 

[york1]

dang George lol

One thing I have learned is if I didn't put it in the tank and i can not ID it 100%. It has to go

 

[skrappy]

Based on the claws, my guess is that it is an emerald crab. I too have had an old emerald crab turn a grey green color that looked almost white, even when he molted he still stayed that muted grey color just with a little more of a green hue. I'm no taxonomist, but I'm 95% sure it is an emerald and 99.9999% sure it is not a gorilla crab. With all that being said, large emerald crabs can eat live fish; if it can grab it and hold on to it, it will start taking bites out.

 

[thomas10152]

A lot of your larger crabs will nip at fish. I was never a fan of having them in the display tank. I normally put them in the sump area if I ever had any hitch hike

 

[itsamyheff]

I’ve had an emerald crab that was red/the reddish color they look once they’ve been cooked. It’s a rare trait, but still an emerald.

The crabs are opportunistic predators, so if they are hungry enough and capable enough, it’s very possible they got ahold of a fish or two.

And I thought I over feed just for that reason. He be gone now.

 

[itsamyheff]

That may be a Gorilla crab Larry. They are similar to Emeralds and sometimes mistaken for one. In any event, I agree with the hunger statement above. Crabs are opportunistic.

Gorilla Crab: A Clawed Hitchhiker | FantaSEA Aquariums

When introducing live rock in your aquarium, it's possible to get more than you bargained for. One of the uninvited visitors that can show up in your tank is the gorilla crab, a destructive and hard-to-catch hitchhiker.

www.fantaseaaquariums.com

fwiw,
I have read that some species of Gorilla crabs may be toxic?

Xanthidae - Wikipedia

en.m.wikipedia.org

Hey Bill. Hope all is well. I was thinking gorilla but no dark claw. I guess he took care of the algae issues and then some. He is in a new home now(the fowler tank). Just can't believe he hasn't been chewed on by the big guys yet.

 

[itsamyheff]

One thing I have learned is if I didn't put it in the tank and i can not ID it 100%. It has to go

The only reason I put them in there was to battle an algae issue that I could not get to go away. I had pulled the others out about 8 months ago. Just never could get this guy out till the other day. He's been fed to the fowler tank but nobody is interested in it.

 

[itsamyheff]

Based on the claws, my guess is that it is an emerald crab. I too have had an old emerald crab turn a grey green color that looked almost white, even when he molted he still stayed that muted grey color just with a little more of a green hue. I'm no taxonomist, but I'm 95% sure it is an emerald and 99.9999% sure it is not a gorilla crab. With all that being said, large emerald crabs can eat live fish; if it can grab it and hold on to it, it will start taking bites out.

I believe so as well. He just stayed the whitish color and had me guessing. When we saw him grab the tang, it was like holy cow, he just did that. We had been trying to catch him for a while. I grabbed him with the tongs once but he wouldn't let go of the rock work. I had to let him go because I had rock work starting to tumble. He's been caught now.

 

[itsamyheff]

Thanks guys for the responses. I had heard of them causing problems before, just never seen it. I can say seeing it grab a fish was a first for me.