In looking at the video from the top, it is difficult to see clearly, but this could be ich or Brooklynella. General Cure, if properly dosed, won't cause a fish to stop eating, so that issue is coincidental with the medication and is due to the original problem. Ich doesn't cause a fish to stop eating until very late in the infection. Based on that, I'd say then, that this is Brooklynella. That disease is tough to treat unless you have formalin. However, formalin is toxic to people and tough to source. Most people then rely on Ruby Reef Rally Pro. That doesn't always work, but it is the next best option. Do you have a treatment tank?
Jay