crab hitchhiker

[ekclark]

I have a number of crabs that came in on some Marshall Island rock. These guys are blue with red eyes. The largest is about an inch across and the little ones are about the size of a dime. They have rounded claws and are very shy. I have only been able to catch a glimpse of them at night. My corals and fish are all okay so far (about five days). I know ids are really tough without a picture, but does anyone have an idea? I didn't find anything when I did a search on this forum...thanks for the help.
evan

 

[ekclark]

Anyone have an idea from my lame clues?

 

[bang guy]

Crabs are nearly impossible to id even from a picture. Color and even shapes of individual crab species can change depending on age, what they're eating, even the weather.
All crabs are predators. the least likely to cause damage and Porcelain crabs and commensal crabs living in SPS coral heads.