Once I move my fish from my long 20g to my 55g I was thinking about getting guppies and platys and was wondering if like say I got 1 male platy with 3 female platys and 1 male guppy with 3 female platys how long do you think it would take before my tank became over run with fry and when a female platy or guppy has babys can they stay in the tank with the other fish or would I have to put in a breeding net? Also how do you tell the difference between a male and female platy and the difference between a male and female guppy? Also can danios go with these fish?