breeding

hi can someone tell me please why my fish is not getting pregnan. I have one man and 4 female platys. two of my platies have just given birth but i have just bought them and they were pregnant i have bought the other two more than 3 months ago but nothing happened so far can someone tell me what is the problem please?

Maybe the other ones are not yet mature. I know this sounds improbable, but female platies sometimes change to males. Of course, that would explain why they're not getting pregnant. In any case, aquarium fish will not reproduce under less than ideal conditions. I have a 20 gallon tank full of red wag platies; none of the females looks very pregnant, but the tank is full of fry. Also, some platy varieties are bad about eating their fry, which are "born" very quickly. For some reason, red wags seem more peaceful than other platies, and they seldom eat their fry.

Please check the water parameters and make sure they are correct for the platy variety you have. Live, floating plants are also a good idea.