ID crab good or bad

Xanthid species perhaps. Crabs are hard to ID unless you personally have dealt with that specific crab type.

http://www.chucksaddiction.com/hitchcrabs.html

Personally I do not like crabs in the display, but I also do not believe in killing every crab I come across so in the sump or back to the LFS they go.

Welcome to 3reef.

 

I agree with Corailline, looks like an emerald crab which is a xanthid. They sell those at LFS but would not be welcome in my DT. IME crabs are clumsy and destructive, the only thing this particular crab is good for is eating bubble algae if you have any.

 

all forms of crab are bad imo

 

I've had two emeralds and an arrow crab in my 40 gallon for about 6 months. I haven't seem any problems they've caused. I'd like to know what problems to look out for.

 

Straight from Chuck's addiction, " None of which can be considered reef safe and can be the most destructive of the crab types. While very small, they seem to pick at algae on the rocks, but just as with other crabs species, once they gain a bit of size, their ability to pick off and eat any number of invertebrates and corals also increases. They also have a bad habit of enlarging their hiding places within live rock and will, in due time, weaken the rock considerably."

Also like i said clumsy, they will knock frags over and possibly rockwork.

 

IMOPE, all crabs are opportunistic omnivores. While juveniles may be content with algae and bits of leftover fish food, they will want- and need- more meatier items on their menu as they mature, even if it means killing tankmates.

 

Was this written specifically about emerald crabs, or crabs in general?

 

The xanthid family of crabs.

 

Xanthids specifically but for emerald crabs it pretty much says the same issues.