Red serpent sea star lethargic

[cemmerts]

Hey guys, I got a red serpent sea star about 9 days ago, drip acclimated for a couple hours, put him in the tank and he did really well. Moved to a dark area pretty quick and has eaten chunks of krill several times without any problems. This am, i noticed he was in the same spot as last night. I tried to feed him and he wasn't interested and just let the shrimp get taken away by the current. He wasn't moving away from my hands either and seemed to minimally respond to me. I picked him up and looked him over and he looks fine. He has a uniform bright red color, no injuries. I set him on a rock out were I can watch him and he is just sitting there with only faint movement in his arms. His feelers are also moving a little. I checked everything and parameters are fine.

Spgrav 1.024
Temp 78
pH 8.2
Ammonia undetected
Nitrate 0.5
Nitrite 0
Phos barely detectable
Cu 0
Ca 400
Alk 7.0

Everything else in the tank is fine. Tank is not particularly seasoned but has always been very stable. Probably due to my OCD testing and water changes and cleaning. The only thing i can think of is that I got a Gyre pump a couple days ago and when I first turned it on, it went full blast and kicked up a bunch of sand, which could have had some trapped stuff that i'm not testing for, so I did a water change just in case. There are a couple bristle worms around as well, could a sting do something like this?

Any ideas?

 

[Flippers4pups]

They can shut down at times once full and digesting. I would not attempt to feed it for a couple days and observe.

 

[cemmerts]

They can shut down at times once full and digesting. I would not attempt to feed it for a couple days and observe.

That would be awesome if that’s all it is. He moved an inch or two overnight, no other significant changes.

 

[cemmerts]

Update: his activity level has slightly increased as I do find him moving a bit overnight and while I’m at work. He tends to stay exposed in the sand, however, I did move him today as my new pump got here and was blowing sand on him while I was trying to get it dialed in. He seems to be loosing some of his vibrant red color now and the tips of his arms are a bit pale and his central disc also is a little pale. I haven’t fed him since Saturday.

 

[cemmerts]

He has started to deteriorate now, has a big wound on his central disk. Hard to take a good picture.

 

[cemmerts]

This am the hole in his disc is large and encompasses probably 80-90% of the disc. His arms are still moving so I’m not sure if I should take him out yet or not. Sounds like this is a common trend and nobody knows why. They start with reduced activity levels then develop a wound which turns into a hole that grows into the majority of the disc. Some theories are eating something to large, trauma, and acclimation.

 

[TriggerFinger]

They are said to only live a few years even in the wild. There was a guy on here who had a black brittle star for about 8 years (I think) and it did the same thing towards the end...it could just be the end of its life.
I have a pretty large one that was in someone else’s tank for at least 3 years so I expect mine to do the same thing eventually and I’ll be so upset too sorry for your loss

 

[Mikedawg]

I would remove asap. Have not read of anyone having good long-term results with this organism and, yes, several theories as to their demise. My understanding is that they feed in nature on decaying matter, plankton, etc. - the kind of food sources found in well established tanks. Even though they are observed to take meaty foods, imho this is not a sufficient diet over time and you usually don't know how long and under what conditions they were kept by exporter/dealer.