Anybody know what kind of urchin this is??

[flyyyguy]

I actually had no idea it was a urchin until I loaded the pic and blew it up.

I found 3 of them on a colony of zoas I have in QT. I kept seeing the fuzzy super bright emerald green thing poking its head out so I finally got the thing out of there and in the process found 2 more.

it is TINY. less than 1mm and all of them were exactly the same size. for several days in a row the one i saw was hanging out in the same little hole in the rock.

are any urchins coral predators out of curiousity??

2nd pic is his underside

 

[LeslieH]

Looks like a juvenile rock urchin, maybe Echinometra. These are grazers that create a home for themselves in the rock. They move about mostly at night to graze micro-algae & organic film from rocks & return to their holes for protection.