A lay follower should not engage in five types of business i.e. business in weapon, human being, meat, intoxicant and poison. But there are many jobs can be considered harmful but not included in the five types of business mentioned in the Sutta.
I have a qualification in music and I want to put this into practice. Is teaching music can be considered right livelihood? Talaputa Sutta says
Any beings who are not devoid of passion to begin with, who are bound by the bond of passion, focus with even more passion on things inspiring passion presented by an actor on stage in the midst of a festival. Any beings who are not devoid of aversion to begin with, who are bound by the bond of aversion, focus with even more aversion on things inspiring aversion presented by an actor on stage in the midst of a festival. Any beings who are not devoid of delusion to begin with, who are bound by the bond of delusion, focus with even more delusion on things inspiring delusion presented by an actor on stage in the midst of a festival. Thus the actor — himself intoxicated & heedless, having made others intoxicated & heedless — with the breakup of the body, after death, is reborn in what is called the hell of laughter.
Teaching piano may not be explicitly mentioned in this Sutta but it is possible for a person who teaches music and for those who are taught to be focused with even more passion, aversion and delusion. Does this livelihood lead us to hell? I believe the majority of healthy, normal people in the most strictest sense will not object to teaching piano. But the Sutta is probably saying otherwise and it can potentially limit your career or business you want to pursue or at worst you can end up unemployed for the sake of keeping yourself on the right path. The antidote to this type of situation is to ignore it and keep going but I don't think ignorance is the right path.
I may misunderstand the Sutta or may not misunderstand it. Hope someone can shed some light, that will be a very helpful and appreciated. Many thanks.