I'm starrting a dual breeding project with corydoras pygmaeus and pseudomugil luminatus in a 15 gal. I have a 5 gallon and a breeder box ready for the fry. The one question I have is, how do you know how many eggs to collect? I'm not breeding for profit but so that the younger generations take the place of the ones before. Do you collect as many as you can but then what do you do with the culls?