ID from Gulf of Mexico live rock
- Thread starter Wanamaker
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Maybe. I’d keep an eye out
jabberwock
2500 Club Member
Looks like a red mithrax. 50/50 in my experience. Great algae eater if you get a cooperative one.
CRABDADDY
Active Member
This guy came in on my live rock from the Gulf as well. Looks similar to yours, but this one I believe is a male. Mine started out small, but grew very quickly. Small fish started going missing. I know he was eating snails as well because I was finding broken shells. I'd remove it and send it to the sump. That's where mine lives now.
jabberwock
2500 Club Member
That is a gorilla crab. Bad crab, you don't want it...
This guy came in on my live rock from the Gulf as well. Looks similar to yours, but this one I believe is a male. Mine started out small, but grew very quickly. Small fish started going missing. I know he was eating snails as well because I was finding broken shells. I'd remove it and send it to the sump. That's where mine lives now.
CRABDADDY
Active Member
Definitely not. He's been banished to the sump where he will spend the remainder of his days. I do enjoy crabs and he's cool, so I didn't want to get rid of him, but he obviously can't stay in the tank.
I'm pretty sure he's still eating all the snails down in the sump. My trochus snails reproduce like mad, so it's no big deal.
Your crab here is the Spineback Hairy Crab, Pilumnus sayi - not reef-safe.
This guy came in on my live rock from the Gulf as well. Looks similar to yours, but this one I believe is a male. Mine started out small, but grew very quickly. Small fish started going missing. I know he was eating snails as well because I was finding broken shells. I'd remove it and send it to the sump. That's where mine lives now.
OP, your crab does look to me like a Mithracid crab, possibly the Nodose Clinging Crab, Mithraculus coryphe - regardless, it's probably as reef-safe as an Emerald Crab.
Wanamaker
New Member
Thank you, I hope you are correct because I returned him to the tank. There is another one in there identical to him, so fingers crossed. I have a rock in quarantine right now with what I am more certain is a bad crab, probably a gorilla crab. It is much fuzzier than the one I caught, and it has black-tipped claws. I'm trying to get him out, but I've had little luck so far. There is also a clicking noise coming from there. I know it could be a mantis or a pistol shrimp, but it seems like the noise is coming from the crab.
I agree with the consensus that its a red mithrax, the TBS rock I received had several similar and they stayed relatively small for a mithrax crab. Also got some red "emerald" crabs which grew huge!
I havent heard of gorilla crabs clicking loudly like a mantis/pistol, i'd imagine you have a small pistol shrimp in there, alpheus heterochaelis if I were to guess. I had to skewer the gorilla crabs out of the rocks to get them out eventually, they are persistent buggers.
Yeah, black-tipped claws are usually an indication you don't want them in your tank. As was mentioned above, the clicking is probably a pistol shrimp (though it could potentially be a mantis too).
Also, I'm a bit late by now, but welcome to Reef2Reef!
Wanamaker
New Member
Thank you for the input and the welcome! I already pulled out one mantis shrimp that was in a different rock. I'm hoping it isn't another.
I just caught the bigger crab I saw in the rock, and a little one came out too. These two look quite different than the one in my first post. These have the defined black claws, unlike the first one.
Now, I'm not sure what to do with them since I have a Red Sea Max Nano XL AIO and not a dedicated sump. I'd feel bad killing them, but can I drop them in the back of my AIO without risk of escaping into the main tank?
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jabberwock
2500 Club Member
I am gonna say no, you don't want them in the back of your AIO. I understand that you feel bad about euthanasia. Not an easy decision. In my book, do your best to make it quick.
Yeah, those aren't ones you want in your tank. If for no other reason than it would probably be too small in the future, I probably wouldn't drop in the back of an AIO (setting escaping aside, I've heard of some crabs doing damage to electrical wires, so you don't want them somewhere they could reach important things).
Personally, I'd see if you can give them to a local hobbyist or fish store (some people like to use crabs like these are food for their predators), or see about setting up a "sin-bin" hitchhiker tank - if neither of those work for you, then yeah, euthanasia is about the only other option; I know clove oil is suggested for fish, but I don't recall if it's effective for inverts too at the moment. Like jabberwock said, aim for quick and painless.
Sump Crab
Valuable Member
This guy came in on my live rock from the Gulf as well. Looks similar to yours, but this one I believe is a male. Mine started out small, but grew very quickly. Small fish started going missing. I know he was eating snails as well because I was finding broken shells. I'd remove it and send it to the sump. That's where mine lives now.
I had one of these in my sump up until the day it decided to tear open my bag of carbon lol
CRABDADDY
Active Member
Mine is sort of a pain too. Even in the sump. He eats all the snails down there. I tried to put an urchin from my tank in the sump for a few days because it was eating coral. I should have known better. The crab killed that too, despite it being far larger than him.
Last week I saw another smaller crab like this in my display
ackshee
Community Member
Just wanted to propose another option that might make you feel less guilty. What if you euthanize the crabs, grind them up, and freeze them to use as fish food? That way they're not "going to waste"
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