Sea Urchin Behavior What are they doing?

[Dr RBG]

These two were put in the DT a few days ago. I noticed them "linked up" today on the glass. While watching them a shower of small differently colored balls came from one of them. Any ideas?

 

[AlSimmons]

They were probably spawning. The link below might help.

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

 

[Maggie321]

The balls are poop. Those don't look like the same species of urchin... but I can't see much of the bodies.

Maggie

 

[Dr RBG]

I got them from Algae Barn and both are supposed to be Echinostrephus sp, But probably just poop like you say but the colorful type at that.