sea urchin lossing spines

[RUCoralGuy]

I've got two seperate systems going, and ~2 months ago, an urchin in one system started lossing spines and died a few days later. Now this morning, i notice in the other system, yet another urchin is losing his spine... and will eventually suffer the same fate as his commrade.
Any ideas on why this is happening... or do they just have short life spans in aquaria? (my systems are 1.5 years old)

thanks in advance!

 

[WRASSER]

What are your water parameters?

 

[Anonymous]

They do it when they're severely distressed. So it's not a good sign. I have a Diadema urchin that did it for a few days when I got it about a year ago. Was growing algae on its spines as well. But then it perked up and has grown considerably since then.

How big is your tank? How long have you had the urchin? Did you have a lot of coralline and other algae growing? I notice mine will graze Halimeda and coralline a lot.

 

[ChrisRD]

Have you checked your salinity lately and how do you measure it?

 

[Anonymous]

Ooooh, good call. Echinoderms are sensitive to salinity change.

 

[WRASSER]

I was thinking more on water tempature :?:

 

[RUCoralGuy]

I measure salinity daily with a refractometer. I have float switches to replace evap loss, so the salinity doesn't change much more then +/- 0.5 during a given day. I have heaters and chillers working to keep the temp a steady 25 +/- 1. My pH is lower then i want it to be, but it is pretty steady b/w 8.0 and 8.2 during the course of the day. I did just do a water change, but the salinity didn't change. However, when i lost my first urchin a few months ago, i hadn't done a water change prior to his loss of spines. I do have calcarious algea growth, and they do feed on it.
I'm hoping the just don't have long life expectancies.

 

[WRASSER]

WOW, the tank sound real nice. It is funny I dont want mine and I cant seem to get rid of it. you want yours and ... .... I really hope you get a hand on it and figure it out. good luck.

 

[Anonymous]

Was it a large water change? Did you see any of the Urchins spawning before they dropped spines? Were the spines laying all around an Urchin that was moving slower than normal? Yes to all of the above indicates osmotic shock.

 

[goby2]

I had a bunch of snails die once that caused the fish to get ich and the urchin to go all limp and lose a couple spines. He came back great and the spines grew back very quickly after several water changes.

 

[RUCoralGuy]

well, he's still alive, but hasn't moved much all day. He's got one spine left, it looks terribly sad. Also, the nubs where his spines used to be are red. Is this a sign of regrowth?

 

[romunov]

Every lost spine is an open wound.
How long have you had the urchins?

 

[RUCoralGuy]

about a year and a half now.

 

[fishfanatic2]

Any possibility that any trace of metals got in the tank? Urchins are very sensitive to copper and other metals, possibly from a water pipe?

Hope it works out OK.

 

[RUCoralGuy]

hmm,... well they are research aquaria, and i'm supposed to be the only person handles the tanks... but we recently had a new PhD student come that thinks she can take samples whenever she wants, and may have used a rusted razor to scrape some xenia off the side of my tank....
hmm?

regardless... the urchin seems to be getting back on his feet, moving around more with his tenticles out and about (crosses fingers)
thanks for all the ideas!