[Spick]

It seems when i bought my FIJI cured LR i had a couple of crabs take a ride with it. At first i was told over the phone they were emeralds. I've done research on emeralds, and most of them are green have furry legs but not bodies. These look similar to emerald crabs. I beleive there are three however, I've only seen two out at a time. they mostly hide all during the day and come out when the lights come out. the one which i am mostly curious about is the FURRY CRAB. He is completely full of hair. almost like a spider would be. Is this a type of Emerald Crab? And is he beneficial to my reef or does it matter, or could he be a threat?

thnx

[zhenya]

Originally Posted by Spick

the one which i am mostly curious about is the FURRY CRAB. He is completely full of hair. almost like a spider would be. Is this a type of Emerald Crab? And is he beneficial to my reef or does it matter, or could he be a threat?

I seriously doubt that it is emerald crab.
Here's a link for you to the article about crabs most likely found in aquariums.
http://reefkeeping.com/issues/2003-12/rs/index.htm

My advice would be to try and remove it. Crabs can be very distructive in a reef tank.

[Spick]

I wish removing it could be easy! I'd have to take out my LR and shake it out. Trust me i don't think i could remove it any other way, atleast that I am aware of. I'll definitely be reading the article tho.

Does anyone else maybe know what type of crab it may be?

[Elmo18]

I'd like to post a link that was really beneficial for me. This is a CRAB ID link. Usually not your common hitchhiking crabs, but does give lots of species with photos.

I think your crab is possibly a common Fiji rock crab, but i'm not completely.

Crab ID

- Elmo

[Ninong]

Originally Posted by Spick

It seems when i bought my FIJI cured LR i had a couple of crabs take a ride with it. At first i was told over the phone they were emeralds.

They couldn't be emeralds if they hitchhiked in on Fiji rock, unless the Fiji rock was placed in a holding tank with aquacultured live rock from the Gulf of Mexico and Caribbean. The person on the other end of the phone should know that they are a Western Atlantic species.

Hobbyists generally refer to both Mithraculus sculptus and M. forceps as emerald crabs, although the second one is a reddish-brown color. They used to be in the genus Mithrax but now they're in the new genus, Mithraculus. They are often recommended as a natural control for Valonia spp. and Ventricaria spp. (bubble algae) but the problem with that is that their dietary habits change as they mature and get larger. When young, they are primarily herbivorous but they become more and more omnivorous as they get larger. The larger ones especially present a risk in reef tanks.

It is possible that the crabs that came in on your Fiji live rock are harmless but it is more probable that they are not. I have heard of aquarists trapping unwanted crabs by placing a small baited drinking glass just under their hiding place after the lights go out. This only works if they pick a convenient hiding place.

[Spick]

Cool.. thnx... after viewing the crab link you sent... I believe what i have is a "Hairy Crab"(Pilumnus Sp.).... can anyone tell me if hes a danger to my reef?