Noob reefer id question

[Patsfann]

Hi all,



I just started my first reef tank two weeks ago and was wondering if anyone could i.d this crab that recently came out. It does not look "friendly" is this something I should be worried about. Thanks for all your help, been lurking the boards for a while.

(Noob reefer, poster, and digital camera user)

 

[MartinE]

Its an emerald crab, he eats the algae valonia I believe. Some folks swear off all crabs, I say see if he does any harm get him out, if not leave him.
By the way :welcome:

 

[Patsfann]

Thx Martin

 

[FragMaster]

Yep,Mythrax Emerald crab. See the bubble algae he is munchin gon in front of him inthe crevase?
That is what he eats.
BUT when they get larger they will pick at corals.

 

[Mihai]

He eats all kinds of algae. Some species get quite large. If he's hungry and an opportunity presents itself it may try to eat a fish. If it stays small and you have plenty of algae (not just bubble) for it to eat he'll probably not chase fish around.

M.

 

[Lutra1]

How common is it for something non-plant to just pop out of your rock and start wandering your tank? I mean, I'd be pretty confused if one of those ugly little buggers just spawned out of my rock. Not sure I want that to occur...

 

[Anonymous]

Lutra,
when ever you buy live rock or corals, there is always the chance that something will survive and crawl out of some hole in the rock. They're called hitch hikers. Some are good and some are very bad. Just the luck of the draw type of thing.

My black mythrix likes to eat hair and some slime algeas. He hasn't bothered any fish, but is big enough to knock stuff over :evil:

 

[Lutra1]

Okay, thanks. Just a little worried that my perfect cute little nano will one day be overrun with little uglies. :? Of course, then I can just deposit the little hitchhikers in my friends tank and pretend they evolved in there. :wink:

 

[Josh Weber]

Hey, I have one in my tank to. It is an emerald crab and I've had no problems with him.

 

[fyrefysh]

I think that this little Mithrax crab is about the only reef safe crab that there is. I have had a few over the years and have had no problem with them. They will not eat fish or corals and they do not get very big. I think the largest that I have ever seen them get is silver dollar size (legs and all).