[da_tahoe]

I just purchased some LR from my LFS and I noticed a large dark colored crab hidden in one of the rocks. I cant see him all the way to get a full picture but he appears large. Most of the time I just see his claws reaching out to the glass and taking the algae off. My concern is if this crab will harm my other tanks occupants. I have a gobie and 14 hermit crabs. I am going to try and attach a pic that I was able to take when it was partially out of the rock. Its not the best pic but its all I could manage. Any help would be appreciated. Let me know if the pics are clear enough for someone to see.

Steve

[zhenya]

Hi Steve,

I can't really make out what type of crab it is but regardless,crab this large has no place in the reef tank. I would try to get rid of it, personally. If you cannot remove it from the rock then remove the entire rock and either flash him out with some carbonated water or pocke him with something
Those black claws look mean(and large) enough to justify harsh actions IMO.
If you have a large enough sump you could possibly keep it there but in the display tank it may cause plenty of trouble when it gets hungry.What their diet is no one knows, plus most crabs are opportunistic feeders/predators.
Just my opinion,of course.

[Poseidon]

I agree, get that sucker OUT!!! He may be just getting used to his new home before he goes HUNTING for new food!

[acropora]

One way to rid your aquarium of an unwanted crab is to use a tall glass. Place a piece of cocktail shrimp in a tall narrow glass or Bud vase. Then at night place the vase next to the L.R. where you last saw the crab. The crab will crawl into the glass and it will not be able to escape since the glass is to smooth and slippery. A tall narrow glass will keep post larger fish from gaining access. You may snag an occasional hermit crab or two, until you capture the targeted crab.
If it is too large for this method, then it is best to hunt it down and physically remove it, as stated above.

[ick sucks]

i cant tell really because the pics are not great but it looks like an emerald crab. if he is green(emerald green) then he is not too bad i think. emeralds eat algaes and will snag a small fish. not sure if they are reef safe. you can buy emerald crabs at my lfs, so maybee its not so bad to have in a reef tank. also remember that crabs that always hide with there claws sticking usally means it a predator. unlike hermits that are out and about-they are scavengers.


good luck