Hunt is over. Large black crab, now behind bars.

[carri10]

Hello all.
About a month ago, I caught sight of a crab that looked like it had hairy legs hiding in a rock. I thought it might be a gorilla. Tried a few bottle traps, but could not coax it out. Today, saw it underneath the rock and whipped the rock out.
Managed to extract the crab and here it is.

Anybody have an ID please?
Thanks very much!

 

[Dburr1014]

Hello all.
About a month ago, I caught sight of a crab that looked like it had hairy legs hiding in a rock. I thought it might be a gorilla. Tried a few bottle traps, but could not coax it out. Today, saw it underneath the rock and whipped the rock out.
Managed to extract the crab and here it is.

Anybody have an ID please?
Thanks very much!

By the looks of the pointy claws, I'd say it's a meat eater.

 

[carri10]

Agreed. When I pulled it out of its crevice, a claw came off first. Very pointy. Not a good sign!

 

[vetteguy53081]

Hello all.
About a month ago, I caught sight of a crab that looked like it had hairy legs hiding in a rock. I thought it might be a gorilla. Tried a few bottle traps, but could not coax it out. Today, saw it underneath the rock and whipped the rock out.
Managed to extract the crab and here it is.

Anybody have an ID please?
Thanks very much!

This has the body of a mithrax crab (emerald crab) who can get this dark and even red in color. Other would be stone crab but I believe emerald which eat some algae but will turn on coral mainly zoas. This is one you can sump. I never trusted these guys

 

[ISpeakForTheSeas]

Hello all.
About a month ago, I caught sight of a crab that looked like it had hairy legs hiding in a rock. I thought it might be a gorilla. Tried a few bottle traps, but could not coax it out. Today, saw it underneath the rock and whipped the rock out.
Managed to extract the crab and here it is.

Anybody have an ID please?
Thanks very much!

Chlorodiella sp., likely C. nigra:

I'm fairly confident you've got a young Chlorodielline crab of some variety there, probably a Chlorodiella sp., possibly C. nigra, but I'm not entirely sure.

The pattern on the legs may change a bit as it ages, and it should develop a somewhat rougher carapace, but it should stay small (adults of most of these species have a carapace size typically right around ~0.4"-0.75" full grown, so it really shouldn't pose a threat to most livestock - no guarantees with corals though) - there are claims that these can reach 8 cm/~3.14" full grown; I have seen absolutely no evidence to support that (even if you include the legs in the measurements).

I have seen one exceptionally large individual with a carapace width slightly less than 3 cm (it was ~1" carapace, and ~6 cm total counting fully outstretched legs); even at that size, it should be around the same size to somewhat smaller than a grown emerald crab.

I have also seen these for sale as "Black Mithrax Crabs" (no, they are not Mithrax crabs, nor are they closely related) - they're purportedly reef-safe, but I've also heard they may eat small inverts (like brittle stars).

They're safer than most crabs, but I'd say probably reef-safe with caution (not many people keep them, though, so that's from a small sample size to work with).

They're technically Xanthid crabs (which are generally not reef-safe), but these are generally very small, and at least one related species (Chlorodiella nigra) is sold occasionally as a "Black Mithrax Crab." I know at least one was kept without causing problems until it was full grown (then it reportedly started eating small inverts), but even emerald crabs are known to sometimes cause issues when larger.

 

[carri10]

Thanks very much indeed. I’ve sumped it to be cautious.
I did some research on the web and found the following,

Chlorodiella nigra Chlorodiella nigra

Chlorodiella nigra is commonly referred to as Chlorodiella nigra. Difficulty in the aquarium: Easy. A aquarium size of at least 50 Liter is recommended. Toxicity: Toxic.

www.reeflex.net

Seems, from this source, it accumulates tetrodotoxin.

 

[ISpeakForTheSeas]

Thanks very much indeed. I’ve sumped it to be cautious.
I did some research on the web and found the following,

Chlorodiella nigra Chlorodiella nigra

Chlorodiella nigra is commonly referred to as Chlorodiella nigra. Difficulty in the aquarium: Easy. A aquarium size of at least 50 Liter is recommended. Toxicity: Toxic.

www.reeflex.net

Seems, from this source, it accumulates tetrodotoxin.

Yeah, Xanthid crabs aren't edible - they won't release toxin into the tank, they just store it to poison anything that eats them.

 

[mtfish]

Yeah, Xanthid crabs aren't edible - they won't release toxin into the tank, they just store it to poison anything that eats them.

I have eaten a lot of stone crab claws. I did not know xanthid crabs were toxic.

 

[ISpeakForTheSeas]

I have eaten a lot of stone crab claws. I did not know xanthid crabs were toxic.

Yeah, Florida Stone Crabs, Menippe mercenaria, aren't Xanthid crabs - they're Menippid crabs (which are actually from a different superfamily).

I don't think all Xanthid crabs are toxic, but many confirmedly are.

 

[mtfish]

Yeah, Florida Stone Crabs, Menippe mercenaria, aren't Xanthid crabs - they're Menippid crabs (which are actually from a different superfamily).

I don't think all Xanthid crabs are toxic, but many confirmedly are.

Cool. I must be getting really old. I still remember keying out crabs using Darryl L. Felder key and he only took it to family (Xanthidae). Looks likes taxonomy and names have changed since the 1980's, lol.

 

[ISpeakForTheSeas]

Cool. I must be getting really old. I still remember keying out crabs using Darryl L. Felder key and he only took it to family (Xanthidae). Looks likes taxonomy and names have changed since the 1980's, lol.

Haha, yeah taxonomy changes fast these days - it's even changed on me a couple of times already, and I've been in the hobby for less than three years.