IDing acro crabs vs baddies

[spidey07]

Is there a tip on telling if a crab on an acro SPS coral is good for the coral or bad?

I have two small crabs on one of mine and I can't tell if they are eating the coral or not. One is furry but they both have very small/narrow shiny black claws.

Thanks in advance.

 

[bertoni]

Well, if you're not seeing damage yet, you might be safe for at least a bit. Can you get a picture?

 

[spidey07]

I'll try later this evening.

I think there is some damage but I couldn't tell if the polyps had been eaten or were just retracted because the crab(s) was crawling around.

 

[spidey07]

well to be safe (and in my newbness) i fresh water dripped the acro, but in hind site it is a millipora (sp?) and took the larger crab out as there was significant damage to the coral. The other smaller crabs seem "safe", they are about 5 mm leg to leg.

Given my small tank I am giving SPS (acropora/milipora) a try as a learning experience. I want to see how they do.

On a positive note the "sickly" acro I purchased is showing more polyp extension every day. It's blue/purple with green circles around the polyp. he also has has a very small crab hanging out on him.

the big guy was hairy and I followed RC advice - get him out.

 

[bertoni]

Sounds okay. I'd watch the other crabs to make sure they stay small and don't damage the corals.