Just like all fish you have to know what you are going to do with your fish long term. If you want babies, obviously, you need a mle and a female. If you do not want babies or do not have room for babies then you want all of your fish to be the same gender. The male's bottom fin is long and skinny. He usually holds it up to his body. The females bottom fin is wide and spread out. She will flaunt it around unless she is scared or under stress.
Like most fish Platys require a large tank, and a strong filter. The common rule for size of tank for most fish is a gallon per inch of fish. That rule applies to Platies. Platies can be kept in a bowl. The bowl should be cleaned once or twice every two weeks to renew their oxygen supply. However, leaving them in a bowl will redue their life span to about 6 months. I do not recommend putting an adult in a bowl. You should breed them and put the babies in the bowl. The adults just do not have enough room to live.
Also, like most fish, Platies are to be fed twice a day. Feed them only enough food that they can eat in two minutes.
Platies live to be about two or three years old.
Platies breed mostly in warm water. If you have a thermometer in the tank (recommended) with green and yellow shaded areas the temperature should be between the green and top yellow for breeding. The fry are born able to swim allowing them to attempt to swim away from their mother when they are born. Their mother will eat them, so I recommend using some type of trap or breeding net. The type of breeding trap that I use is a plastic box with small openings in the sides for water current to go through and give oxygen to the mother and babies. You can put the container in the tank with the other fish along the side. In the bottom of the container is a "V" shaped plastic thing with a space in the bottom. When the babies are born they fall into the "V" and into the bottom of the contraption. Leave the mother in the container for a couple hours to let her recover before putting her back into her regular tank. Platies will give birth about 6 times, once every 30 days to about 30 fry each time with the males help only before the first litter! Some people say to put the mother in a separate tank with lots of plants, but this option seems too dangerous to me for the babies (even if the babies can escape into the plants from the mother, they will still get curious and wander out of the plants) if you want to keep and raise them. (Which is a lot of fun!) Also, there is a breeding net which I would NOT recommend because you put the mother and the babies in the same net!
(actual size of new borns)
Feeding the Babies
The babies should be fed 3 times a day. Most websites will tell you 6 times a day, but I only feed mine 2 times a day. They should be fed crumbled fish flakes. What you should do is put a pinch of flakes in a plastic bag, and pinch the food until it is a fine dust. This may take a while and if the babies are a week or so old you may be able to feed them bigger, but still crumbled, pieces of food.