If i have followed everything going on correctly, Conan seems to have had health issues going on for an extended period. There is a disease called fish TB, which is a bacterial infection that takes a long time to kill. One of the trademark signs of this is a bent S shaped spine, which I think i am seeing in the last picture. Other signs can be pop eye (the bulging eye in the first pix, look at the left side)? It is also very hard if not impossible to cure, which is why it would not have responded to antibiotic medicines you have used.
I just feel terrible not being able to help the poor little things