First, read the English article below.

The body shape of male and female guppies is very different and distinctive. Male guppies usually have very slender, long bodies, while female guppies are usually a lot rounder and bigger than the males, sometimes twice as big as a male guppy.  If your female guppy is pregnant, her body may look boxy or stuffed and even lumpy. She may grow even rounder as she gets closer to birthing her young.  You may want to use a magnifying glass to get a better look at your guppy’s shape, size, and coloring as it swims around in its tank. You may want to try to do an approximate measurement of your guppies to help determine their sex. Female guppies can grow up to 2 ⅛ inches (6 cm) and are often a lot larger than male guppies. In contrast, male guppies can grow up to 1-⅛ inches (3 cm). Male guppies are often much more colorful than their female counterpart and their bodies may be covered in bright coloring and patterns. Males may have bodies and tails covered in orange, blue, violet, green, black, and white spots and stripes. They use this coloring to attract a female mate. Keep in mind that spotting a lot of bright colors and patterns on your guppy is not a sure fire way to identify it as male. Some types of guppies have females who are also quite colorful, so you may want to use other physical markers to determine the sex of your guppy in addition to coloring.  You can look at different breeds of guppies online to determine what breed your guppy is as well as the different coloring and patterns on your breed's tail. While you are examining your guppy’s body shape and coloring, you should go a bit closer to your fish and check for a gravid spot. The gravid spot is a dark spot located on the underside of your guppy’s body, near the tail, and is a clear marker of a female. Males do not have a gravid spot. A pregnant female guppy’s gravid spot will get darker and bigger as she gets closer to delivering her young. As her due date approaches, you may be able to actually see the babies inside her, close to her gravid spot.... 

Now, please write a short abstract for it in Vietnamese. Abstract:
Kiểm tra xem cơ thể cá thon gọn hay tròn trịa. Lưu ý kích cỡ của cá. Quan sát màu sắc sặc sỡ và hoa văn trên cơ thể cá. Tìm chấm mang thai dưới đuôi cá.