How long have you had this fish? Did you quarantine it?
How long did you have your Yellow Tang and when did it die? Did the Yellow have any visible spots? Erratic swimming, flashing and heavy breathing are all signs of parasites and since you are dealing with Tangs, its very likely the cause
Now if your Yellow was new, died quickly and had these symptoms, it could be marine velvet. Marine velvet kills quickly, often by the time the fish shows visible signs it is too late as the parasite attacks the gills first. If there are visible signs, it will appear the fish has a 'Dusting' of white, gold or grey. This dusting is sometimes hard to see..If it is indeed Velvet, you would need to act fast. Moving the fish to a qt and treating with copper.
Ich is not as deadly as Velvet and is easier to cure. Fish will flash, twitch, dart around , sometimes they breath heavy and some fish will hide. Within a few days you will see spots like salt. This is easily treated [if caught early] with Hyposalinity or copper.
Do watch your fish, be prepared to move him to qt if he continues this behavior