Crab id help please

NASAGeek · Feb 12, 2023

Howdy!

I was doing my water change and weekly maintenance this morning and saw a crab in my tank. I don’t have any though.

Kind of a cool surprise, but I am now wondering if he’s safe for my coral and fish. I did buy live rock several months ago. I guess it’s possible he’s remained hidden all this time. Attempted to get a pic but by the time I installed an orange lens he was gone. About 2 inches max. Hairy looking but not orange like “Florida hairy crabs” I’ve seen. He appeared very dull colored under the early light. Brown or khaki.
Including bigger photo for reference. Looks like he might have eaten a head off that torch. Hard to say. Hopefully he will help with that GHA instead if eating coral. My tan is too small for a tang.
Thank you!

neonreef3d · Feb 12, 2023

does it look like this?? if so its a gorilla crab,,, get it out.. not too safe ..

NASAGeek · Feb 12, 2023

neon_reefer said:
does it look like this?? if so its a gorilla crab,,, get it out.. not too safe ..

neon_reefer said:

My Kessil was at 1% so it was super hard to see him. I don’t think the claws were multicolored like that. He looked all one color, hairier and was the exact same shape as emeralds I’ve had in past days. Thank you for the reply!

ISpeakForTheSeas · Feb 12, 2023

You're probably going to need pics of it under white light for a solid ID.

ISpeakForTheSeas said:
Some crab ID advice: take a pic of the front like you did (mainly to show the claws - good job there - but also a little to show the face), and also take a pic of the back of the crab (take the pic from above the crab looking straight down at it - this shows the shell and back of the crab, which can both be important for ID too).

ISpeakForTheSeas said:
some top-down photos of the crab's back (including some that show the portion of the shell by the crab's back legs) may be helpful with ID

NASAGeek · Feb 12, 2023

ISpeakForTheSeas said:
You're probably going to need pics of it under white light for a solid ID.

copy that. I’m watching for him while I do maintenance on all the freshwater tanks. (Beer clink)

vetteguy53081 · Feb 12, 2023

NASAGeek said:
Howdy!

I was doing my water change and weekly maintenance this morning and saw a crab in my tank. I don’t have any though.

Kind of a cool surprise, but I am now wondering if he’s safe for my coral and fish. I did buy live rock several months ago. I guess it’s possible he’s remained hidden all this time. Attempted to get a pic but by the time I installed an orange lens he was gone. About 2 inches max. Hairy looking but not orange like “Florida hairy crabs” I’ve seen. He appeared very dull colored under the early light. Brown or khaki.
Including bigger photo for reference. Looks like he might have eaten a head off that torch. Hard to say. Hopefully he will help with that GHA instead if eating coral. My tan is too small for a tang.
Thank you!

From the body and tips on claws,, im convinced it is a Xanthidae crab which is undesirable in the tank. Pics under white lighting can help confirm

NASAGeek · Feb 12, 2023

vetteguy53081 said:
From the body and tips on claws,, im convinced it is a Xanthidae crab which is undesirable in the tank. Pics under white lighting can help confirm

Just found a second, smaller one. Appears to be the same species but far less hairy at this size. He’s about 1 inch.

Uncle99 · Feb 12, 2023

All crabs bad IMM.
Removed all 5 years ago.
No longer any mysterious deaths or unhappy corals.

Fish Styx · Feb 12, 2023

NASAGeek said:
Just found a second, smaller one. Appears to be the same species but far less hairy at this size. He’s about 1 inch.

You have yourself a gorilla crab there. You'll want to trap and remove it.

NASAGeek · Feb 12, 2023

Fish Styx said:
You have yourself a gorilla crab there. You'll want to trap and remove it.

Ok thank you. I got a better pic of the bigger one, as well.

Fish Styx · Feb 12, 2023

NASAGeek said:
Ok thank you. I got a better pic of the bigger one, as well.

Yup. Kill it with fire. The striped pattern on the legs, as visible in the previous photo was the dead give away. Well, that coupled with the "hairy" appearance.

NASAGeek · Feb 12, 2023

Fish Styx said:
Yup. Kill it with fire. The striped pattern on the legs, as visible in the previous photo was the dead give away. Well, that coupled with the "hairy" appearance.

Thank you so much for the reply! I appreciate it

vetteguy53081 · Feb 12, 2023

NASAGeek said:
Just found a second, smaller one. Appears to be the same species but far less hairy at this size. He’s about 1 inch.

Hmmm- may be a decorator crab

ISpeakForTheSeas · Feb 12, 2023

The pics are a bit better, but still pretty blurry. That said, based on how “hairy” it seems to be and the fact that it seems to have “hair” on top of its shell, I’d guess a Pilumnid crab of some kind (possibly a Pilumnus sp.) - again, you’d probably need clearer pics for a solid ID (but, personally, I’d sump it at this point to be safe).

Pilumnid crabs aren’t technically gorilla crabs, but they’re gorilla crabs (i.e. not reef safe) for hobbyist purposes.

Fish Styx · Feb 12, 2023

NASAGeek said:
Thank you so much for the reply! I appreciate it

No worries at all. Do you have a trap, or know how to make a bottle trap?

NASAGeek · Feb 12, 2023

Fish Styx said:
No worries at all. Do you have a trap, or know how to make a bottle trap?

I do not, but I just did some searching on the idea. Sounds easy enough. We’ll try tonight when the lights go down. Thanks!

NASAGeek · Feb 12, 2023

ISpeakForTheSeas said:
The pics are a bit better, but still pretty blurry. That said, based on how “hairy” it seems to be and the fact that it seems to have “hair” on top of its shell, I’d guess a Pilumnid crab of some kind (possibly a Pilumnus sp.) - again, you’d probably need clearer pics for a solid ID (but, personally, I’d sump it at this point to be safe).

Pilumnid crabs aren’t technically gorilla crabs, but they’re gorilla crabs (i.e. not reef safe) for hobbyist purposes.

Copy that. I’ll try to catch them. Thank you for the info. My iPhone is a potato. My kid has a new one. I suffer because… more tanks. Haha