Only certain types of discrimination, those specifically made illegal by a statute (that is, by a law), are illegal. The main types of prohibited discrimination are against someone due to their race, sex, religion, age over 40, or disability. There is no protection for personal appearance (other than appearance due to race, age, religion, etc.), so it is not illegal discrimination to terminate an employee due to his or her hair. Also, there is no obligation that employers generally treat employees fairly or the same--they can punish person A for something which persons B, C, and D also do, for example--so an employer could choose to fire one multi-colored hair employee but not others. d on what you write, this appears to be legal.