Strange Crabs out at night

[JM]

Tonight when i got home from work i decided to take out the flashlight and checkout my tank to see if there was anything new crawling around. Didn't c anything too spectacular just the normal little critters running around on the rocks, not quite sure what they all are, but i'm sure you all know what i'm talking about if you look at your tanks at night. There is all kinds of life out and about. The one thing that did startle me was two decent sized crabs. Identical to emerald crabs in shape and size, but with dark brown almost black shells and white fuzzy legs. Any ideas what they are or if they could be a danger to any of my corals or other inhabitants. It looked to me that they were picking food off the lr just like emeralds do so maybe they won't hurt anything. Just wondering if anybody else has these.

 

[MT79]

I had a crab fitting that exact description hitchhike into my tank. Long story short, it ended eating about 3" of an SPS overnight. Just about all crabs are a risk- especially as they get bigger.

 

[JM]

Well i dont have any sps, but hearing that makes me want them out of there asap. Guess its time to make some traps.

 

[DurTBear]

Do they look like this guy? I found this guy a couple weeks ago and I have no idea what kind of crab he is. He seems to have a little friend too as I discovered another tiny crab (too tiny to get a pic) but can't ID him because he only sticks out his legs and sometimes uses them to grab food during feeding time.

 

[JM]

Nope, his legs look similar, a little less fuzzy, and his body is smooth and shiny, and very dark.

 

[DurTBear]

I think if his body is smooth and shiny, it's a part of the mithrax family like the emerald crab so it should be reef safe. But I like everyone else's advice on crabs and would probably try to catch it and take it to the LFS. I think my guy is really cool looking but if I can catch him, I will because I don't want him eating corals or anything like that.

 

[melosu58]

If you do catch him JM just add him to your sump. He will be OK there. You might need to use the tilted glass trick.

 

[JM]

Thats probably what i am going to try. Tonight when i get home i'm gonna c if they are near the same spots and see if i can narrow down what rocks they are living in and just take the rocks out during the day and look for them.