Red Crab Identification Help Please

[jombolo]

I cannot figure out what species crab this is. The fish store had it labeled as "red crab" which is just way too generic, theres gotta be an actual name. Its beautiful though, and have had it for about a month, gets along well with my emerald, hermits and cleaner shrimp that photo bombed my pic. I see it mostly in the mornings sitting on this section of rock that protrudes out of the water and sometimes on the bottom scavenging in the sand, but i think it mostly hides in the rocks.

 

[Easy E]

I believe that is a female fiddler crab. We also had a LFS that was selling them as red crabs. They need to breathe oxygen periodically to survive, so that's why it keeps crawling to the surface. The LFS didn't tell me that, so I killed 2 of them before I figured it out. It's lucky you had some protruding rock or it would probably be dead already. I think it's pretty unscrupulous to sell them because they are shoreline/tidal creatures and not really suited for aquarium life unless you have a specialized set up for them. I'm sorry, but I doubt if it will do well in your tank long term. I hope you didn't pay too much for it.

 

[jombolo]

I only paid $5 I have two places where it can breach the surface on live rock. So far, it has done well and seems to have a similar diet as an emerald crab. I wonder about your comment about needing to breach the surface for air....as I recall the tank it was in at the LFS, I don't think it had the ability to breach. Either way, its colors are striking and I hope it does well

 

[Easy E]

They can survive for several days without air, but eventually need to breathe. I'd be willing to bet if you went back to the fish store there wouldn't be many left alive in their tank. In the wild they retreat to their burrows during high tide and only become active again once the water recedes. That would obviously be a difficult environment to replicate in an aquarium. Most, if not all, of their feeding is done on land, so if yours is eating, that's a good sign. Maybe putting some bits of food on the exposed rock would improve the odds of long term survival. Good luck!

 

[jombolo]

Yeah, I will def try that out. After google image searching fiddler crab, this seems to be on the generic side, some pretty crazy color combos out there. Maybe it will eat mysis shrimp

 

[Easy E]

There are about 100 species of fiddler crabs, so I'm sure they come in a myriad of colors. The eyestalks and the shape of the shell are what makes them similar. It sounds like they will eat almost anything, but live mainly off detritus. You might try a variety of different foods, but I'm guessing that stinkier is better to a fiddler crab. Another potential problem is that they usually live in brackish areas so they may have trouble to acclimating to the salinity of a reef tank.

 

[Calappidae]

Uca sp.

Yeah, they're an intertidal species that need land and water like regular fiddlers.

This species I'm not too familar with but the majority of fiddlers are indeed brackish water. (Despite what 90% of the fish store owners tell you.)

Do you have an idea where he was collected?

 

[Betta132]

They need a tank with at least a third of the area made of sand/rock/etc, and they're brackish water. Good for a species tank, not really a reef thing.