Hitchhiking crab ID please?

TikiBird · Oct 21, 2017

I got a new piece of live rock last weekend, and this morning I saw this crab type creature crawling on it! He’s since disappeared back into the rock.

I’ve looked through some ID sites and can’t find him. I also can’t tell if he’s hairy. He was so little. Maybe like 1/4inch? Here are the best pics...I was so surprised and he disappeared fast!

Any ideas? Good crab/bad crab?

DSC reef · Oct 21, 2017

That does not look friendly. I'd remove it until a positive ID can be made.

TikiBird · Oct 21, 2017

DSC reef said:
That does not look friendly. I'd remove it until a positive ID can be made.

Will do. I will take out the rock he’s on. Not sure how I will lure him out of the rock, but at least he’ll be contained.

Edit to add: The rock is in a container. Hopefully the mushroom corals on the rock will be ok in there for a bit.

DSC reef · Oct 21, 2017

I'm wondering if the crab will come out if you leave the rock out of water for a period of time.

TikiBird · Oct 21, 2017

DSC reef said:
I'm wondering if the crab will come out if you leave the rock out of water for a period of time.

I think it might but I have some mushrooms attached to the rock....

I still have it in the container. Maybe I’ll try to lure the crab out with some food?

DSC reef · Oct 21, 2017

The mushrooms are pretty resilient. Try food but the water temp change in a separate bucket long term will do more damage than leaving the rock dry for 15 to 20 minutes. Hopefully he will come out.

TikiBird · Oct 21, 2017

DSC reef said:
The mushrooms are pretty resilient. Try food but the water temp change in a separate bucket long term will do more damage than leaving the rock dry for 15 to 20 minutes. Hopefully he will come out.

Ohhhh I see. Okay, yes. I will try the food in a bit and see if he goes for it. Thank you!

kyleinpdx · Oct 21, 2017

TikiBird said:
I think it might but I have some mushrooms attached to the rock....

I still have it in the container. Maybe I’ll try to lure the crab out with some food?

as long as they stay wet they should be alright, mist with a spray bottle or use a dropper to drop some tank water on them.

MamaLovesHerReefTank · Oct 21, 2017

Looks like an emerald crab to me. If it is you can put it in the tank. Just to be sure I would wait for a few more to chime in for positive id. Any chance you can get a clearer picture?

TikiBird · Oct 21, 2017

Ok, I’ve got the little dude!! Thank you for the tip on removing the rock from the water, @DSC reef! He didn’t come out on his own, but I could see him down in a hole, and I saw the hole went all the way through the rock, so I was able to poke him out the other side.

Here he is....who is he??

kyleinpdx · Oct 21, 2017

TikiBird said:
Ok, I’ve got the little dude!! Thank you for the tip on removing the rock from the water, @DSC reef! He didn’t come out on his own, but I could see him down in a hole, and I saw the hole went all the way through the rock, so I was able to poke him out the other side.

Here he is....who is he??

IMO Those black claws say gorilla crab. If so, good that hes out. If you have a sump/refugium you can banish him to I'd suggest doing so.

EriksOasis · Oct 22, 2017

Gorilla crab. If I’m wrong he is still not good for a reef tank.

TikiBird · Oct 22, 2017

Ahhhh glad I was able to get him out then! I have a Biocube29 and he’s so little right now I’m actually paranoid he’d be able to slide through the back chambers and get into the main tank.

I think I’m going to take him to the LFS tomorrow and see if they want him to feed to a triggerfish or something. I hate killing creatures but I don’t want him in my tank either....

Ranjib · Oct 22, 2017

Good move, its not an emerald crab for sure :0-)

MamaLovesHerReefTank · Oct 22, 2017

TikiBird said:
Ok, I’ve got the little dude!! Thank you for the tip on removing the rock from the water, @DSC reef! He didn’t come out on his own, but I could see him down in a hole, and I saw the hole went all the way through the rock, so I was able to poke him out the other side.

Here he is....who is he??

Definitely not an emerald. Gorilla more likely. Not good for the tank.