Gorilla Crab Question

[fftfk]

I bought some live rock from TBS (not a critique - would buy again) and believe I have a gorilla crab. Two ground dwelling gobies have been killed and two others are missing. This morning - I think i found a crab not moving out in the open which I got out of the tank.


It is hairy and I think a gorilla crab. Seeing as I found it out in the open and not moving (even when scooped up) I think it is most likely dead, my questions are:

Do gorilla crabs molt? It seemed to be a solid crab I pulled out with some mass and not a hollow out shell so I think it's actually the dead crab.

If it is dead...is there a worse predator in my tank that could have taken the crab out?

One of my gobies was paired with a pistol shrimp. Would the crab have killed it? I haven't seen it since the goby disappeared but still seen new burrowed holes? Plus the crab was out in the open near one of its holes. Maybe it killed the crab?

Thanks for any help!

 

[dendrite]

make a bottle trap, set it out at night and see what you can catch. Think Mantis. All crustaceans molt. Open up the carapace and see if there's flesh inside, otherwise your well fed gorilla molted. If truly dead then think even larger gorilla or mantis shrimp.

 

[donut0079]

I would think that is probably a molt. Crab molts are very different than shrimp. They are solid and can very easily be mistaken for the actual crab. If you are seeing burrowing the pistol is probably fine but it is not capable of killing a crab.

 

[fftfk]

Thanks - I've been trying traps to catch it. Nothing so far. It's interesting that both the gobies died but I have three burrowing wrasses that have been fine

 

[fftfk]

The gorilla crab is definitely alive...I just saw him. The hunt continues!

 

[fftfk]

I spent an hour and a half hunting the gorilla crab tonight. Here is him getting closer to the trap!
https://vimeo.com/141015207
At the last second he ran away...a few minutes later he was back...getting closer to the trap...and in!!!!!
Here is the emerald crab I enter catching:

When I realized it was the wrong crab I looked in the tank and the gorilla crab was standing out in the open staring at me.

Good news is my pistol shrimp is still alive! I did definitely see it.

 

[Bent]

In my 40lbs of Rock I ordered I have about 4 gorilla crabs. I started with 7. I managed to catch 3 with a quick hand and tweezers. Just like Mr Miyagi taught me.

So I have 4 left to catch. 3 of them are tiny, but one of them is pretty big and I can't seem to get him out so he can go to the sump and play with the stone crab that's in there.

Keep looking, I bet there are more.

 

[adoptaspork]

i had a gorilla crab sneak into my tank once! he kept running into a small island rock and so i dipped it in RO water and he came scuttling out to his demise.

 

[fftfk]

Got him!
https://vimeo.com/142761619

 

[SoloGarth]

This is why starting with dry rock is better. On my last setup I had one of those guys living in the tank for years. I didn't know until I replaced all the rock with new dry rock in order to have control over all inhabitants. I found the gorilla crabs dried out body in my garage where it had climbed out of the bucket that I had put some of the rock in. I kept the body as a reminder of what can make its way in if you aren't careful.

 

[fftfk]