What Are the Differences Between Male & Female Betta Fish?

Betta fish are common aquarium animals prized for their beauty. It is easy to determine the sex of most adults, although the differences between younger fish are less pronounced. In addition to physical differences there are behavioral differences that can be used to distinguish males from females. They are easier bred young in the fishes' lives.

  1. Description

    • Betta fish can be found in a variety of colors and tail shapes. Wild Betta are usually greenish brown or gray to aid in camouflage, although their captivity has enabled breeders to engineer brighter, more colorful fish. Adults are 2 to 2.5 inches in size.

    Male Appearance

    • Adult male Betta fish are easily distinguished by their long fins, nearly twice to four times the length of their female counterparts. While fins are shorter in adolescence, the observation of growing, tapering anal fin indicates a male. In general, males are more elongated and less wide than females. Their colors tend to be brighter and more in variety as well. Males have a membrane under their gill covers, sometimes called a beard, which is displayed when open, but still visible when closed.

    Female Appearance

    • Adult female Betta fish are easily distinguished by their shorter fins. All females have egg spots, tiny white specks, located on their bellies between the ventrals and anal fins. Occasionally, adolescent males have this spot as well, but will carry it into adulthood. Females have a similar membrane to males' beard, but it is not visible when the gill membranes are closed. Today, female Betta fish are bred for longer fins and more color variations, making sexing more difficult.

    Behaviors

    • Male Betta fish blow bubble nests to house eggs before breeding while females do not. Males flair their beards to intimidate each other, although sometimes aggressive females display a similar behavior. Males are territorial and will not tolerate the presence of other fish. They have been known to flare their beards at their own reflections.

    Breeding

    • Bettas are best bred early in live, between half a year and a year old. The female must be small enough to allow the male to wrap himself around her body. Once the eggs are lain, the male Betta takes full responsibility for them, gathering them up in their mouth and depositing them in a bubble nest. After the eggs are in the bubble nest, the female must be removed from the tank, as the male may recognize her as a threat to the eggs and attack her.