You should check the Department of Labor website and look at the fact sheets on tipped employees and all of the examples they provide. In brief, yes you must pay minimum wage. If the tips do not equal the wage, you must make them up. However, you should make sure you understand about tip credits and how they apply and what you must do to take tip credits. Also, if you have an employee who is getting poor tips due to performance, then you can obviously take care of that situation through probation, suspension, warning, termination, etc.