Hi Craig,
how old are your fish ?If they are of breeding age then you should be seeing some pairing off?flirting in the tank if so they are the ones you need to put into your breeding tanks or get what you think is a female you want to breed with a put 2 possible males that you would like to breed with her in the tank and see what happens.all the best.33 fish is alot if they are adults.
cheers