Depends. You can put in some fish (if there isn't already some fish) in your tank that will eat the fry and can stand up to the aggressiveness of a Convict pair, or you can grow up all of those fry and sell them/give them to other owners and fish stores in your area. I will admit the last option will require more work so I think the first option would be better.
Also, since you now know you have a male and female pair of Convicts, maybe move one to another tank (if it doesn't cause to many problems) to prevent another outbreak of fry.