Sea urchin shedding it's spines!

[srwmemphis]

I have two black sea urchins that I have had for almost a year now that came on some live rock and was so small I didn't even see them for about a month. They have grown to a size of about 2.5" to 3" across. My tank is in the best shape it has ever been in.

In the last two weeks, I have noticed 10 or more of their spines laying around the tank. On the live rock and on the coral sand floor. This is the first time this has happened since I have had them. It appears that the lost spines are coming from both of them. I haven't added any new livestock or moved the rocks around.

Do they shed spines and then re-grow them or what?

[mbeach66]

i've read before that when sea urchins start to shed their spines its likely that they are dieing, im sorry to say. try feeding him meaty foods and if he takes hopefully it will work. have you had any cases of microbubbles in the tank? that may have caused the problem.

[srwmemphis]

Yes, I do have some very fine bubbles but I always have had. The spines appear to be cut off about 1/4" to 1/8" from the body and almost look like they are getting new growth. I don't know.

I have never fed them before! Is that wrong? The only thing I have on hand as far as meaty foor is frozen brine shrimp. Would that work?

Thanks

[topQuark]

Sea urchins are very susceptible to nitrate levels, have you checked your nitrates?

We had a small pencil urchin in our nano which came with some live rock we bought, unfortunately it started loosing spines and died shortly there after. Our nitrate levels in the nano were apparently too high for it. /ubbthreads/images/graemlins/frown.gif