Is this starfish wasting away?

[Marine_Addict]

This red knob was bought a month ago which has been in the shop for over 3 months

I kept it in my fish only system, the para is about 50ppm nitrate and 28 ℃

I recently found there is little erosion spot(or decaying spot??) on the underside of the libs from one to many in a couple of days(which is slowing progressing to the current status as shown in the pic)

so whats the problem?
is there any way i can save it ?
It seems that when the process starts on the star there is no way back? He is eating fine now and nothing problematic on the upperside

 

[Dallascowboys16]

This red knob was bought a month ago which has been in the shop for over 3 months

I kept it in my fish only system, the para is about 50ppm nitrate and 28 ℃

I recently found there is little erosion spot(or decaying spot??) on the underside of the libs from one to many in a couple of days(which is slowing progressing to the current status as shown in the pic)

so whats the problem?
is there any way i can save it ?
It seems that when the process starts on the star there is no way back? He is eating fine now and nothing problematic on the upperside

I honestly can't see a whole lot wrong with him assuming the giant yellow blob is food that he's eating and not some sort of infection. Typically though when a starfish starts to erode even a little bit it is extremely difficult to reverse the process.