Crab ID?

[Reygan2]

I found one basically identical to this in my tank. I've been trying for days to catch him, using a trap I bought online and the glass leaned against the rock method. Nothing is working. I believe it's responsible for the death of my hi fin goby and a peppermint shrimp. Any other ideas? The rock where he resides is the base of my entire scape and I'd really like to avoid having to remove it to get him out.

 

[Sniperhank]

No way did it kill your fish. It might have cleaned up the corpse, but that is what crabs do. I wouldn't keep a crab like that in a reef tank, but if it is fish only it should be fine. There is another reason for your recent losses.

 

[Reygan2]

No way did it kill your fish. It might have cleaned up the corpse, but that is what crabs do. I wouldn't keep a crab like that in a reef tank, but if it is fish only it should be fine. There is another reason for your recent losses.

I've heard from too many others that certain crabs can and do kill resting/sleeping fish. Still can't catch that sneaky thing either.

 

[MacDracor]

No way did it kill your fish. It might have cleaned up the corpse, but that is what crabs do. I wouldn't keep a crab like that in a reef tank, but if it is fish only it should be fine. There is another reason for your recent losses.

Exactly what he said.

 

[bribo12]

I disagree. That looks like a gorilla crab (xanthid species) and if so could have definitely been the cause of the gobies disappearance. They are not a good hitchhiker.

 

[MacDracor]

Xanthid crabs are destructive in that they undermine rock work and will feed on invertebrates, but it is extremely unlikely it is killing fish unless it is very large and the fish was sick or trapped. And if it did kill the fish, there would have been a considerable amount of flesh removed from the corpse before it was found.

 

[bribo12]

If it was some other fish and not a goby and peppermint shrimp I would agree with you. However the peppermint makes sense so I'm gonna say it possibly got the goby as well. Did you ever find a body?

 

[mr_X]

I had big sally lightfoot crabs in my tank recently and they literally chased fish from time to time, right before my eyes, however, even as big as they were, they could not catch a fish. I even had a small mandarin in the tank that was never bothered. Crabs just aren't set up for ambush predation. The same goes for Mithrax and Xanthid. I have kept plenty of pretty large emerald crabs. They didn't bother anything, except maybe pick at some soft coral here and there.

 

[Reygan2]

If it was some other fish and not a goby and peppermint shrimp I would agree with you. However the peppermint makes sense so I'm gonna say it possibly got the goby as well. Did you ever find a body?

I searched and never found a shred of the body. I found that odd.

 

[Reygan2]

I had big sally lightfoot crabs in my tank recently and they literally chased fish from time to time, right before my eyes, however, even as big as they were, they could not catch a fish. I even had a small mandarin in the tank that was never bothered. Crabs just aren't set up for ambush predation. The same goes for Mithrax and Xanthid. I have kept plenty of pretty large emerald crabs. They didn't bother anything, except maybe pick at some soft coral here and there.

My goby slept in a hole at the bottom of a rock, only one way in/out. The crab lives there now.

 

[aherbert]

I have a 4 inches one in my Reef tank because never could Get it. Is safe

 

[MacDracor]

I would argue that no crab is completely reef safe, simply that some people have been very lucky with their individual crabs.