pin cushion urchin.. good or bad??

[jennmac415]

Ok, the other day I was at my favorite LFS after a very long vacation ( had to have my "fix) and my son (haha) just had to have one of these tiny, about 1 1/2 in. in diameter white pin cushion urchins. All has been fine so far, nothing knocked over, mostly staying on the glass. But today I am noticing that it is starting to venture onto my rock and everywhere it goes, the rock the it has passed over after doing its thing is totally and completely WHITE!!!!!! And I mean void of any color what so ever. Is my whole rockscape going to eventually be colorless??? YUCK!! What should I do? Take it back?? Up my calcium doses??

Help I don't want to have a colorless "base" rock tank!!

Thanks,
Jenni

[Phishnoob]

Mine died...so can't help.

I am not sure if it was Spanky or another esteemed poster but consider them the same as a starfish.

[jennmac415]

someone??????????????????

[Patman]

they eat coraline algae....so thats what you are seeing...

Pat

[Geoff]

yep, a lot of urchins eat algae. some have very strong teeth for scraping off corraline. they can be bad in acrylic tanks.

you may find that your coraline algae takes off. the scraping releases coraline spores which can then attach and grow new colonies.

G~