Fight it, unless you signed a contract saying no pets were allowed. But snakes can't cause damage to a house so there's no reason you can't have them, the only time I've had to tell a tenant anything like that was when they moved in with a pitbull they didn't tell us about but only because of insurance reasons for us we had to ask them to either leave, or get renters insurance which they did. I just started helping manage apartments with my uncle so i don't really know much about that but i don't think even we can get rid of someone for that but I'll try to find out, i think you can fight it though.