What are the laws for youths working in Iowa?

I'm 16 years old and I work for my dad. He refuses to pay me minimum wage because he says that the law says that as long as I work on the family farm (he doesn't even have a farm, just a large house), he doesn't have to pay me anything. He's been saying the same thing for the past 3 years while I've been doing handyman jobs for $0-5 an hour. Can he do this or not?