Found a mysterious crab that I've never seen before today

[Zukari]

Anyone have any idea what kind of crab this is? I've not been able to keep SPS in my "mostly" stable reef tank for a very long time. I definitely did not purchase this crab... and he doesn't look like any crab I've seen in my search for pest crabs. He was actually under an acro frag.

 

[Zukari]

The only thing I can find that looks similar is a Black fingered mud crab..

 

[Sierra_Bravo]

I wish I could see the claws better, but appears to be a red mithrax or red clinging crab to me. Are the claws pointed or do they terminate by coming together with a flat surface? A red mithrax is shown below. It's a cousin to the emerald crab, and the shape of the claws mean it primarily eats algae off the rocks although almost all crabs can be opportunistic feeders.

Welcome to R2R, by the way!


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[Zukari]

I wish I could see the claws better, but appears to be a red mithrax or red clinging crab to me. Are the claws pointed or do they terminate by coming together with a flat surface? A red mithrax is shown below. It's a cousin to the emerald crab, and the shape of the claws mean it primarily eats algae off the rocks although almost all crabs can be opportunistic feeders.

Welcome to R2R, by the way!


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Thanks for the welcome! Long time lurker.

He was difficult to get a picture of for sure, the most interesting thing to note is his legs have no "hairs" of any kind. For lack of a better term he was smooth all around. I decided to imprison him in the sump. Likely a coincidence but my LPS and SPS look better after removing him.

 

[Sierra_Bravo]

Sump looks like a good place for him.