i would agree in not wanting oscars to mate. they lay 2000+ eggs and they raise at least half of them! then your stuck with 1500+ oscar fry that you cant sell. what you could do is when they lay the eggs remove them from the tank
let them breed if they want to. if any end up surviving, donate them do a lfs for store credit or something. jus dont attempt to take care of them if you dont intend on keeping any, maybe the parents will just eat them. but dont stop the oscars from mating if they choose to. atleast there happy enough in your tank to try.
i agree, if its their first time,then the eggs will probly not survive, its a trial and error thing for fish.they get the hang of it around the 2nd time.
thats kinda the point of having a male and female fish though,to have babies.if you think differently then you should have fish of the same sex instead of opposite.