Here's some reading that is on topic...unfortunately perhaps not ultimately useful since there just isn't much to do with sick starfish:
http://www.wetwebmedia.com/linckiafaqs.htm
I thought this response was really interesting...I bolded an interesting part that I have never heard of before:
"Re: Orange Linckia (Target Feeding Deposit feeders/ Sea stars) What is the best way to feed these guys ? 29 gal tank with 2 bags live sand and 35 pounds of live rock. Tank only a couple of months old. <hmmm... going to be challenging here to be honest. Most would say the tank is too small to conceivably support a sea star. If possible, small daily feedings of a great variety of foods (green and meaty). Perhaps consider making a homemade food recipe (many on the net and in Bob's book, on WetWebMedia, etc)... freeze all in party cube trays and offer the star a food cube daily (mixed nutritious fare with vitamins) from the substrate> Have 2 clowns, 1 horseshoe, <Doh! er... Horseshoe crab? Forgetting the adult size of about 12" in diameter... there will be no easy way of providing enough food in the sand to keep this crab alive in such a small tank. Too bad... indeed a fascinating creature. My string advice is to get this crab to an aquarist with at least a 200 gallon tank and DSB. In the meantime, bury mysids in the same place daily just under the sand (other meaty foods too of course for variety)> 1 linkia,2 skunk cleaners shrimp. I feed spectrum daily as well as Mysis shrimp (every other day), I have a few shrimp left on the sand when creatures are done eating.
Can I hand feed a Linckia??? <yep> Small children perhaps?? <only if they misbehave or seem inclined to vote Democrat in the future> Thanks a lot for your response. Ron <my great pleasure... best regards, Anthony>"
Reefin101, my pure speculation as to what is going on with your linckia is that it was feeding on something in the tank that is now gone and it is slowly starving. This happens to a lot of animals that feed incidentally in the tank without supplemental feeding by the owner. If he's gong downhill, perhaps experiment with some hand feeding of mysis or perhaps some Fauna pellets if you have? I doubt it will work though as I think the linckia is probably doomed as mc-cro stated.
