is this normal for a diadema urchin?

[fmelindy]

Just bought a new urchin a couple of days ago. He moves around but hasn't eaten anything yet. He shows a preference for being on the sand bed to the point where he just "leaps" off the rocks when I put him there ("leaps" meaning he just strolls off) and spends a fair amount of time upside down and flipping over constantly. He was acclimated over an hour with a drip system and all water parameters are within normal limits. He seems healthy otherwise. Anybody else with experience with these urchins to let me know if this is normal for a new introduction?

[Nlangan]

My longspine was a hitch hiker so I don't know about behavior when introduced into the system. But I can say that mine spends no time on the sandbed. I don't really find him on the glass either. Just cruises around on the rocks. I also have a short spined (pincushion type) hitch hiker and that guy is highly mobile. He spends most of his time on the glass and the rocks but he also cruises across the sandbed. Basically they go where the algae is. Maybe you have some on your sandbed?

[noahm]

FWIW :

Wiki (http://en.wikipedia.org/wiki/Diadema_urchin) "D. setosum is more commonly found on sandy sea beds or damaged back reef.."

[fmelindy]

no algae on the sandbed whatsoever. sounds abnormal, eh?

[Dadekster]

We are keeping who knows what kind of sand with live rock collected from some region or other and then expect fish and inverts from many times different oceans to coexist with things from other oceans in fake salt water all being held in plastic or glass boxes with machines keeping everything within a certain tolerance.

Yeah, I'd say that's abnormal. ;)

I have a pincushion and he is almost always on the rocks or back panel. Can't really comment on your species. Maybe there is sometime you can't see he likes on the sandbed though? Being upside down I would say is cause for concern however.