Does this Purple Tang look to have disease?

[RollTideReefer]

So I need some help from you all. I have had all the fish in my tank for over 45 days now. I have had the purple tang in question for about three months. This week I had a torch coral randomly die on me, I noticed a dead turbo this morning, and now I noticed some white coloring or discoloration on my purple tang. I may be paranoid but it is like a discoloration around his eye and then forms a line up his back and towards his dorsal fin. I have attached a video. Though after seeing pictures online he doesn't look to have ich. Keep watching through the video to get multiple looks. I appreciate the help.

 

[GoldeneyeRet]

HLLE. Head and lateral line erosion.

 

[h2so4hurts]

Yep, HLLE, happens when they're very stressed. The death of your torch is probably a clue your tank parameters are off

 

[Aquatic Lifeline]

My friend, you need to test your water.
How old is your tank?
What size is the tank?
Purple Tang definitely has lateral line disease. It's a bacteria that eats away at the flesh of the fish when the fish is stressed.
If your water parameters are good and nitrates are low and your fish are getting a healthy diet, The next culprit would be bullying. Tangs are notorious for bullying each other. And that can cause stress too. But with your touch going down, chances are you have parameters that are out of whack.
Take a sample of your aquarium water to your local fish store and have them test it for you.