They are egg scatterers in a sense, but do not breed their whole quota in a single day...
Practically the whole bottom of your tank needs to be covered with a layer of peat moss or similar strata and over a period (3/4days), they will scatter their eggs in the substrate (around 20 to 30 eggs per day)...
If they are fed an abundance of live Daphnia, mosquito larvae and bloodworms.... the fry may even survive with the parents in the tank. - they do however need special water conditions and are easier to breed than it is to hatch and rear the fry.