Hitchhiker on Acro

[Anonymous]

Got a new acro this weekend and noticed two crab hitchhikers. Don't have a pic yet but will try to get one. They are small, one about 1/4" wide at most the other smaller. Both are white with a black face. The black runs along the leading edge of the crab right across the eyes. Seem to only stay in the acro. Noticed this morning that one move over to another acro in the tank.

Are these guys safe or do I need to get them out of there??
ID would be helpfull also.

 

[Anonymous]

http://www.reefs.org/phpBB2/viewtopic.p ... highlight=

Pete,

Check out this thread. It's kind of describing the same crab you have and it's not so friendly to your tank.

Let me know if it's the same.

 

[Charlesr1958]

That is a "bandit" crab that is commensal with branching corals and is perfectly harmless, I get them all the time when ever I collect any branching corals and have had one hosting a small coral colony for a year now with no ill effect to the coral. In the wild, such crabs actualy defend the coral from other coral predators.

Chuck

 

[Anonymous]

I've got a bandit - So my understanding is that they are reef safe and actually got for the acro.

 

[Meloco14]

I agree with charles. Most of the time acro crabs are perfectly safe. I believe some species filter feed, while some feed off of mucous secreted by the coral. In both cases it's a commensal relationship. The coral protects the crab and the crab protects the coral. I have had an orange crab living in my pocillopora for 2 years and he's never left the coral.

 

[LeslieH1]

Yup. The crab in Charle's image is Tetralia rubridactyla and everything he & Meloco said is correct.

 

[SnowManSnow]

never had any trouble with the acro crabs. just interesting little guys to watch.