This is very similar to an episode that my late flower went through. All water params were fine, I didn't have any ammonia or nitrites. Hopefully its just the ammonia. I contacted several importers who seemed to think it was some type of seizure or even a stroke. Nothing to verify this though. She was never the same afterwards. She was umbrella'd for a couple weeks as if she had some type of damage, muscular or internal I could not say. She was a bully when feeding before episode and timid afterwards. I ended up separating her for quite a few months she became aggressive feeding again. So moved her back with the others where she again became bullied and had her food stolen. After two years I ended up losing her even after separating. She was the only ray I ever lost.
I might still have the video of the episode, will try to find it and post it for comparisons.
Here is the vid....am uploading it now to you tube (will be available shortly). It took me a couple of minutes to get the camera and start videoing. Parts that I missed were her swimming like this and banging into the sides of tank and the driftwood, completely out of control. Hopefully yours isn't for the same conditions and/or symptoms.
[YT]q2RIX5rElVg[/YT]