My reef urchin is doing something Ive never seen before, sheding his spines and as you can see below, the new ones are smaller. Now before he was in this set-up, I had him in my old 120 gallon reef but now since he's been in my 29 gallon Nano. Question is, is he now doing this due to lack of space?
Has anyone else had other urchin species do this?
Hope my reply is not too late to help you.
Your specimen is not doing it due to space constraints...but it is related.
Smaller volume, less stability inherent in system, RIGHT?
Ideal Parameters:
SG - close to, or full strength
T - species origin dependent, on Tropical Reef
Alkalinity - Min NSW levels 2.5mEq/L
NH3,NO2,NO3 - 0 0 minimal
and absolute MINIMUM heavy metal presence!!!
I have had it happen, it is NOT PLEASANT.
Outcome is often fatal, and usually happens in a matter of days.
Here's some reading to help you
Ron Shimek's Sea Urchin article
The fact that the spines are covered, in whole or in part, with living epidermis in most urchins has an important implication for their care, by the way. If you have a sea urchin, and it starts to lose or "drop" spines, that animal is in very serious and probably non-recoverable trouble. Each dropped or lost spine represents an open wound on the surface of the animal. While one or two spines may be lost from time to time, the wholesale loss of spines results from malnutrition or disease and leaves the surface of the body open for massive infection. Such an occurrence generally represents a terminal condition. The urchin typically dies within a few days of when it starts to drop spines.
Either way: Good luck in re-establishing stability, in your urchin's environment.
Read the article, return to forum with results of your efforts.