The main methods to distinguish between male and female betta fish include observing their body shape, color, the size and shape of their fins, abdominal characteristics, and the position of the genital pore.
Body Shape and Color:
Male betta fish usually have a slender body shape. Their colors are bright and gorgeous. Common colors include red, purple, blue, green, etc., with high color saturation and strong contrast.
Female betta fish, on the other hand, are relatively shorter and plumper, and their colors are more dull, mostly gray, brown, or light yellow.
The Size and Shape of Fins:
The dorsal fin, caudal fin, and pelvic fin of male betta fish are usually wide and long. The tip of the dorsal fin is sharp, and when the caudal fin spreads out, it is as magnificent as a fan. The pelvic fins are long and filamentous, looking elegant when the fish swims.
The fins of female betta fish are relatively smaller. The dorsal fin and caudal fin are shorter, and the pelvic fins are shorter without the filamentous extended parts.
Abdominal Characteristics:
The abdomen of female betta fish is usually white and bulging. This is because during the breeding period, they need to accommodate fish eggs, and there will be an obvious swelling in the abdomen.
The abdomen of male betta fish is relatively flat and does not have this characteristic.
The Position of the Genital Pore:
There is a white-yellow genital pore between the pelvic fin and the anal fin of female betta fish, which is a key characteristic for distinguishing between male and female.
Male betta fish do not have such a genital pore.