Please Help Me... Something Is Wrong With My Black Spotted Eel :(

[MaggieLenny]

I have had my black spotted eel for almost 5 years now and he is my buddy - always been healthy and active... anyways something is terribly wrong with him, not quite sure what it is, but he does not swim around the tank, instead he cannot control himself and the direction or movement of his swim. He tosses or rolls if he attempts to move (once again no control). I originally did not see anything physically wrong with him, I got my water tested and so on and they said everything was perfect.. he was panting a lot, but that has calmed down a tad, but now I have noticed that the spiny parts of his spine seem rubbed raw or worn down which seems to be from when he braces himself between things so he doesn't have to swim.... and just today his back looks severely bent or broken, yet he is aware.... He doesn't really eat anymore either.. I believe partially because it is such a struggle to reach/swim to the food (mysis shrimp)

Please provide any thoughts, I am at a complete loss here.... this has been over a duration of a week or so.. Thanks in advance