Hey Guys. Thank you for all of your feedback. I'll address some of the stuff you guys raised as best I can:
Weight Issue: You guys are right, he's a little thin right now, and so you know, its been that way for about 2 months now. He's slowed on the eating. He use to eat 2 silversides a day (and was plenty fat), but has been less interested in eating. He still eats around 1 silverside a day. I provide a large mix of food to try to stimulate eating, bloodworms, ghost shrimp...etc. You guys are not wrong about him being thin, but his owner is taking care of him.
Placed in a Bucket: When I first some him sick this morning, I panicked and wanted him away from the tank mates, I know i should have taken out the tank mates instead, but catching those small fish is a pain and I was again worried. Sprinkles is now back in the tank and hopefully recovering.
Tank Mates: I've removed the Tiger Barbs from the tank if there is even a chance of them causing the issue. I don't believe it is the tiger barbs because I have never seen them bother him in 2 years. But, i'm always willing to be wrong, I just wouldn't think they are the cause. Its too extreme too quickly. I have left the Bala Sharks in the tank because those fish are barely aware of their own existence and don't bother anything or anyone.
I've read online and one thing caught my interest; a fellow stingray owner realized that he had burnt his stingray with fresh water salt. He described the injury as a "Darkened scab, that slowly peeled off the skin, revealing white flesh beneath" and that it was "sudden". Well, this description is almost identical. I would be so angry with myself if this is what happened, when i do a water change I add a little fresh water salt. I would think I would notice pouring the salt onto my ray, which I don't think I did, but again, I absolutely could be wrong. I'm surprised too because man, that salt dissolves quickly, if that's what caused the burn then man, I'm such an idiot.
Venom, thanks for the support.
Thank all of you too, I have bought a antibacterial, but I'm afraid to use it.
Here's a vid of him from about a year ago, Healthy and Strong:
[video=youtube;xqAC7NIcGAg]http://www.youtube.com/watch?v=xqAC7NIcGAg[/video]