[SIZE=16pt]Some very good advice [/SIZE]
All guppies do well when kept between 68-74 degrees Fahrenheit
many fish keepers believe that a tank temperature should be constant which is not entirely true,
When kept without a heater a room temperature can fluctuate.
a few degrees in fluctuations will do no harm to fish,
if you only have or use one heater it will be best for the fry the higher temp- will help to grow them on a bit faster,