Inturder Alert!!

[Johnny Cakes]

Okay, I knew it, I knew I wasn't crazy and saw a crab the other night when the lights were out and I was looking at th rocks with the moonlights on.

I got a new batch of LR from the LFS and that is when I started seeing him.

He was dark (well the tank was dark) and I remember he had hairy legs.

This morning I wake up and see an exoskeleton on its back in the sand, so this guy must have moulted last night and now I know he is in there.

The right claw is bigger than the left one and it is maybe about 1/2 inch across on the body.

If I post a pic of the moulted skeleton, will this help to id him or do you need to see the live specimen?

Also, any ideas on what he might be from the limited info, and should I go through the trouble of trying to trap him?

Thanks for the help.

 

[Fluff]

Could be a rock crab. A pick of the molt would help if you can't get a pic of the crab. When they are this small, they aren't much of a threat. They will just scavange on scraps found in the tank. As they grow though, they can (and most likely will) become a problem. They will eat snails and are capable of taking down small slow moving fish. Especially at night while they sleep. You could try catching it using a tall smooth sided glass. Lean the glass against the rock you last seen the crab on. Chances are he's still holed up on that rock. Lean it and place a piece of meaty food (shrimp, fish, scallop, krill, etc.) in the bottom. The crab should go in for the quick easy meal but won't be able to climb the smooth sides of the glass to get back out. hth

 

[Johnny Cakes]

Here he is.

 

[Fluff]

Looks like a mythrax crab. Simular to the emerald crab. It will consume algae and isn't as big a threat as some other crabs. But it's a crap shoot really. They are omnivores. Young crabs tend to lean toward being herbivores but as they get bigger, they will scavage and should be watched. Those flat cup type tips on the claws are used for plucking algae from your rocks. I'd say keep it and watch it. HTH