brittle star - top of head wide open? why?

[rodding]

My britle star has a wide open hole on the top of its head/body. It is now about the full size of its head/body. What is happening? Just this morning three legs fell.

[rodding]

if the legs are moving should i watch them over the next couple weeks??? will they regenerate?? all that is in the tank are two pieces of live rock and two true percula clown fish.

[rshimek]

Hi,

Your brittle star is dying; the damage you described is too severe for any regeneration.

The most common cause for this type of damage is malnutrition, seconded by improper salinity.

To learn about how to keep these animals, see this article, then this article, then, finally, this article.

[rodding]

I started the tank with CaribSea live sand 20lbs and two medium size live rock and about 5lbs live rock rubble in the filter. Tank is 55gallons. i waited one week and started to get brown diatom bloom across sand, I tested the tank repeatedly for nitrite, ammonia, nitrate, PH, temp, SG.

nitrite-.0
ammonia-.0
nitrate-0
PH-7.9
temp-80
SG-1.0245

the second day of adding the sand and second day of new tank, I had ammonia at .7 and nitrite at .2. over the week these levels dropped off to zero. A brown bloom established across the sand. I thought I was in the clear. What other tests or should I let the tank cycle more over two more weeks. And then test the levels and watch everything.

[rodding]

gonner.

[aaron23]

... how long did you wait for your tank to establish? 1 week?

[bertoni]

And how did you acclimate the animal to your tank?

How are you measuring SG? This article might help you make sure your device is accurate:

http://www.reefkeeping.com/issues/2004-06/rhf/index.php

The animal might have been in marginal condition when you got it, so your tank conditions might be reasonable, yet the animal had problems with acclimation shock.