How to tell male from female guppies? A quick guide to identifying males and females

The guppy is a tropical ornamental fish of the genus Poecilia, family Poeciliidae, suborder Cyprinodontoidei. Its rich colors, varied shapes and strong reproductive capacity make it highly favored by tropical freshwater fish keepers, but many people do not know how to tell male from female guppies. Let's take a look below!

Morphological characteristics of guppies

1. Male fish: The caudal peduncle and caudal fin of the male account for about 2/3 of its body length. The caudal fin comes in various shapes such as lyre tail, round tail, flag tail, crown tail, triangle tail, swallow tail, upper swordtail, lower swordtail, double swordtail, spear tail and needle tail (different from the disease "needle tail").

2. Female fish: The female can reach a body length of up to 6 cm, its caudal peduncle and caudal fin account for more than 1/3 of the whole body, and all its fins are shorter than those of the male. Its body color is much less impressive than the male's, mostly a single silvery gray; although there are some patterns on the caudal fin, none are as bright as the male's.

Identifying male and female juvenile guppies

For juvenile guppies, if development is generally normal, fry of about one month old can usually be identified as male or female. If they are still hard to distinguish after more than a month, it may be that poor food or water quality has slowed the fry's growth and development. At the same time, it is also affected by factors such as temperature, food, strain and individual differences, and being about a week faster or slower is normal. At this stage, sexing may not rely on methods used for adult guppies such as "pointed or round anal fin", but males and females can still be distinguished before the anal fin undergoes obvious changes.

1. Males color up first: Generally speaking, male guppies color up first.

2. Look at the rear part of the belly: In young females, the color inside the belly is visible (the precursor of the "gravid spot" in adult females), while young males have a white belly covering it, so the color inside is basically not visible.

Identifying male and female adult guppies

1. The female's color is also less vivid than the male's. The male has very large fins, a very beautiful body color and many patterns, while the female does not: her fins are short and small, her body color is plain and she has no gorgeous patterns, but females with patterns on their fins are of better quality.

2. The male's tail is relatively large, while the female's tail is relatively small. An adult male is about 3 cm long with a short body, and the tail part accounts for about two-thirds of the body length, and can even be larger. An adult female can reach 5~6 cm in body length, with a long body and short caudal fin, the tail part accounting for more than one-half of the body length, and the tail is usually black.

3. The male's anal fin is a long rod, while the female's anal fin is fan-shaped. The male's pelvic fins are slender with a small hook at the tip, while the female's pelvic fins are broad and short. The male's characteristics are a smaller, slender abdomen, and the key point is that its anal fin has evolved into a gonopodium used to deliver sperm during reproduction, so the several fin rays at the front of the male's anal fin are relatively thick, while the female's anal fin is uniform.

4. Only females have a gravid spot; males do not. The male's whole body is covered in beautiful patterns, so the internal organs in the abdominal cavity cannot be seen, while the female's body is rather transparent. If a black spot appears at its anus, it indicates that it is pregnant (some strains have a red gravid spot). The larger the gravid spot, the closer it is to giving birth.

5. If it is a guppy of 1~3 months that has not colored up, you can only look at the anal fin: a pointed anal fin means a male, and a round anal fin means a female.