Say you bought a trio or pair of guppies in the hopes of breeding them for fun. Assuming the females and male fish purchased are fully mature when brought home, they should be ready to start pumping out babies in no time flat! Under optimal conditions, female guppies can produce a spawn of 40 to 60 babies (also known as fry) every 28 to 32 days.
They may not do so in the first month if they are not quite ready, but after 45 days one can expect to start seeing baby fish in the aquarium. Once you see your first guppy fry, it is good to know how quickly they can be expected to grow.
Guppies are live-bearing fish which means the mothers give birth to fish that are already hatched and able to fend for themselves. They have fins and are hungry right from the start. Guppy fry will start looking for foods within minutes. If fed adequately, they can fully mature within 2 to 3 months.
At approximately half of an inch, they are born at a decent size. Within a month they can easily reach one inch, but will likely be thin and lack much color. Once color starts to develop, changes can be noticed almost daily, especially on the males!
By 30 or 40 days of age, this species of fish is able to mate and the males should be separated from females if selected breeding is desired. Fully formed and mature fish can be expected within 2 to 4 months. These fish will have nice flowing fins and full muscle mass! To ensure that your baby guppies develop at a normal rate, feed them a variety of foods several times per day and to change the aquarium water on a weekly basis.