Mithrax Crabs

[NOTORIOUS LEE]

Hi,

Can anyone give me more info on these crabs?

Are they bad or good to have in a reef tank?

Are they also known as emerald crabs?

[rottielover]

Mithrax = emerald crabs

I have about 10 of them in my 120, they eat algae, and I see them munching on hair algae all the time. Though they don't eat a lot, they just arn't that big. They are fun to watch, but shy, mine hide in the shadow's of the rock work during the day, and I only rarely see them "out" in full view. At night they tend to go eveywhere, but they still stick to the rock work.

My personal opinion is that they are a good addition, as they use those little claws to pick algea out of cracks in the rocks etc, especially if you have an abundance of algae for them to graze on. I've heard mixed rumors and reports they they can eat fish if hungry, but I really don't see how, none of mine are big enough to catch anything but the smallest of fish, however it could be that in a 120 the fish have plenty of room to get away from them...

[wharyat]

I agree with rl, I have 1 in my 20 but I rarely see him, he's mostly only out at night. Great for hair and other algae control, have heard some cases where they can eat fish and such. They do eat coralline but it grows fast enough that he can't even dent it.

I say go for it, cool little crabs.

[ski1297]

I have one in my 38 gal got him to eat some algae. Have only had him for about 1 week looks good eats the algae that I wanted him to eat. I have some coral does not even look at it. Does not try to eat my fish. My wrasse did try to eat him but he was way to big for the wrasse. I would say a good carb to have.

[motorslave]

I have one too. Mine isnt all that shy and is realy cool to watch!

Robert