I had some experience with Guppies and I found they were tough and easy kind to keep as long as some conditions are fulfilled :
* Water aeration must work well.
*Don't give excessive food. The food given in feeding time must be eaten up completely in less than 15 minutes to avoid methane formation.
*Don't mix it with more superior fish like Flower Horn which harms guppy's life.
*Guppies can live with real water plants, so giving water plants in the tank is a good idea.
*Guppies can easily breed, thus hiding places like small rocks which are arranged to be made like small caves are needed to keep their newly born offspring safe.
*when a female guppy is pregnant, you'd better separate it from male guppy, to avoid cannibalism when the offspring is born.
*Don't give too strong water pump in the tank and put a sieve onto the pump inlet to avoid guppy and baby guppy to be sucked in water flows.
I hope this answer help you keep guppies in the tank.