Green Brittle Star losing spikes

[jeanacrouch]

My green brittle star has been losing spikes, starting at the tips of it's legs and continuing back. He is now missing about half of his spikes. What is wrong with it? I have a 55 gallon tank with live rock and zooathid coral. two blue damsels and an arrow crab. 4 emrald crabs, a lot of medusa worms. various hermit crabs and snails. The tank has been up and running for almost a year and a half.

[Woodstock]

Welcome to ReefSanctuary!!

We need more information. Please post the following water parameters:

• Temp
• NitrAtes
• PH
• Salinity
• Ammonia
• NitrIte

Maybe the arrowcrab is chomping on it? Arrow crabs are notorious for eating anything they can catch!!
How long have you had the starfish?
What type of water circulation/filtration do you have?

[jeanacrouch]

Originally Posted by Woodstock

Welcome to ReefSanctuary!!

We need more information. Please post the following water parameters:

• Temp
• NitrAtes
• PH
• Salinity
• Ammonia
• NitrIte

Maybe the arrowcrab is chomping on it? Arrow crabs are notorious for eating anything they can catch!!
How long have you had the starfish?
What type of water circulation/filtration do you have?

The temp is 76
ph is 8.3
salinity is 1.021-1.022
As for the others, don't have a test kit for them, but had water checked recently as LFS and all were normarl.
I have two powerheads w/undergravel filter
hang on back filter w/ two carbon pads
I have another filter in the tank that has carbon & foam in it that gets cleaned regullarly. I have had the starfish for about 6 monthes at least. I am still kinda new at this even though I have had the tank for a year and a half. There is so much to learn....

[Woodstock]

Reef Aquarium Water Parameters by Randy Holmes-Farley - Reefkeeping.com

The salinity is low. Shoot for 1.026'ish. Raise it very slowly over several days... during water changes would be a good way.
I am guessing your nitrAtes are very high leading to illness and/or the arrow crab is eating the starfish.
Consider removing the arrow crab.
NitrAtes for inverts should be at 10 ppm or less. Purchase a nitrAte test kit (salifert or API) and test it asap. I suggest doing large water changes of 20-30% every other day until the nitrAtes are at 10ppm or less.

[jeanacrouch]

I had my alkalinty close to that, then the LFS told me it should be lower. I get bad info everytime I ask anything.

[Woodstock]

That doesn't surprise me It is important to do your own research.... read, read, read.

BTW.. your green brittle starfish, when healthy, is a fish eater. They can trap and eat fish successfully.

[jeanacrouch]

I did know that, but with only the two damsels i'm not real worried. Haven't had much time for the tank with our new baby, so i am not planning on adding any new fish for awhile. When i do the brittle will probably go back. Another question, I have been feeding him krill and marine cuisine pieces. The LFS suggest live goldfish, didn't have any luck with that. Should I be feeding him something different?

[Woodstock]

The krill and marine cuisine are fine.
Never sustain a marine animal with fresh water foodstuff.
The composition of marine and freshwater fish, shrimp, etc. is very different and a dangerous imbalance will occur.
A freshwater 'treat' every now and then (rarely) is okay.