Urchin Problems?

Sorry to here about your misfortune Jwin.

I want to get an urchin for my 29g, so I can have 3 clingfish(they have a simbiotic relationship with corals & urchins, eating parasitic bivalves off of corals & often resting againtst corals when they sleep to use as shelter. Clingfish will also use the uchin as protection to hide from potential predetors).

I've seen some sites recommend a longspine urchin, but they get 10"...isn't there a smaller kind, similar to the longspine I am talking about?

 

Yeah I'm thinking it's gotta be the new CUC members we got. They're fine now. But also we've been having some big problems with our torch coral's sweeper tentacles coming out and playing h*ll on other corals. Those things could definitely go between the spines of an urchin, and they aren't exactly "toxin" related, so that wouldn't be an issue.

So those are my two theories since our water is crystal clear and all of our other corals are happy and healthy. Now that we've separated the bullies anyways.

 

What kind of urchins were these?
If they were not active to begin with, they may have been already on their way out.