Platys not breeding

[zrossk]

For some reason i can not get my platys to breed. i have 14, 5 males 9 females. They are with 2 cory catfish 2 glofish and 2 giant danios. I dont think they got eaten because one time i bought a pregnant one at the pet store and it had fry 2 days later and i was able to save 18, there are plenty of hiding places. Three of them are very big but ones a male so i dont know if they are just fat. i have had them for 3 months the tank is 30 gallons and 80 degrees. Can anyone help?

[Angel keeper]

Try to have a look at the females and see if you notice the gravid spot near the anal fin and see if it has turned black or dark in colour, if you see that then the likely hood of them being pregnant is pretty high, that is how i look at the guppies to see if they are.