I am not sure. Looking at your posts last 4 pages, it does not seem that he is sick but he is just not happy. Don't feed him much, I find that Magnifica does not eat anywhere near as much as Gigatea or Haddoni. Remove the shrimps is the right call IMO. Just watch him for a few days then decide what to do next. If he deflates, then treat him but if he just decline, I would just watch him.
Do you have option of move him to a different tank?
I do not have another tank @OrionN
I will get one if I have to though.
I do have powerhead and heater but no light.
Also, it has not been fed in months.