Urchin's

[Young Frankenstein]

Exactly how do they clean the fish tank and eliminate nitrates?

[KMP]

"Sea urchins are to most shallow subtidal marine ecosystems what grazing animals such as bison or cows are to terrestrial communities. "


more than you ever wanted to know about a sea urchin :D

http://www.reefkeeping.com/issues/2003-11/rs/index.php

[woodycb]

I have never heard of an urchin eliminating nitrates from a tank, but I do know they are very intolerant to nitrates. I went through 2 tuxedo urchins to figure that one out. If you are going to own an urchin keep the nitrates as low as possible.