Help with a black urchin

My black long spine urchin was in great shape at the end of May, lots of long spines and moving all over the glass eating algae. Now he is almost spineless, and under a rock, not moving out in several days. His couple of remaining short spines are still waving, so I assume he's still alive, but on his last "legs". LFS said maybe the other fish are "picking" on him, specifically a yellow angel. My tank doesn't produce alot of algae, I think because everyone in the tank are algae-eaters (Blennie, goby, tangs, foxface, the angel, starfish, cleaner crew). I introduced some seaweed placed under a rock near him, the hermit had a ball with it, but I don't think he moved. I'm afraid he's starving. Any thoughts?

 

How is your water quality? Has there been any big swings in salinity? they are very sensitive to that. If you can rule these out I would say it sounds to me like he is starving to death. I feed mine sheets of nori 2 or 3 a week. You also feed them Pleco Algae tabs.

 

http://i37.photobucket.com/albums/e99/bbsbliss/DSCN0715.jpg - That's his "before" pic, I'll post the after when I can get a good shot of him under the rock

 

Actually, my salinity was low a week ago, after a recent water change. I did my chemistry over the weekend, everything came out good but the ALK was a little higher than it had been- I've been adding calcium trying to get a colt coral to come around. Do you think if I put him in isolation with hand feeding I could get him to come back?

 

I would not more him form the environment he is in already. As I said they are very sensitive to water quality and salinity swings.
A major loss of spines is not usually a good thing, it means it is stressed and moving it to another tank would stress it out even more.
I would attempt to feed it where it already is at.

Out of curiosity how old is your tank and how is your water testing?

 

I did a 30% water change(110 gal tank) 13 days ago, tested chemistry 5 days ago, everything was good EXCEPT salinity was a little low, and ALK was a little higher than it had been. I was having problems with my protein skimmer, readjusted and now its working fine. I was using conditioned tap water for my salt mix, and maybe that is the culprit? I test before I do my changes, and let the mix sit 24 hours with heater. I was looking on the web, and everything I can find says a loss of spines is due to poor water quality. Maybe I have a copper or heavy metal problem. I don't want to loss this urchin, and at worst I don't want to lose the whole tank! I think I might be in trouble

 

To be honest with you if you have that many algae eaters and haven't been supplementing its diet since may I am leaning more toward starvation than anything else. They eat algae and if its not there to eat then they starve.

If it was copper or something like that you would most likely have notices other invertebrate problems.

 

whats your SG at? a little low to some people is 1.019 and to others is 1.024

 

Salinity is 1.019

 

thats really way low! Should be at a minimum of 1.023 for most urchins as far as I know. How long has it been that low?