Short-finned Bettas, which are also called Plakats, are sometimes bred to have D-shaped tails. [4] X Research source Since female Bettas typically have shorter tails than male Bettas, it can be challenging to determine the sex of short-finned Bettas.
The veiltail is long and flowing. [6] X Research source It arches up and over the body, resembling a veil. [7] X Research source The tail is usually asymmetric and broad at its base, and more pointed at its outer edge. The half-moon tail looks like a half-circle or a capital ‘D. ’ The perfect halfmoon shape has a spread of exactly 180° between the top and bottom tail rays. Sometimes, the half-moon shape can only be seen when the betta flares. [8] X Research source Halfmoon tails are usually very fragile. There are also ‘over half-moon’ tails, which extend beyond a 180° tail spread angle. [9] X Research source Delta tails are in the shape of a D but do not achieve a 180° tail spread angle. [10] X Research source Delta tails are sometimes called ‘Super Deltas,’ with a tail spread angle of 160° to 179°. The Delta tail usually has rounded edges, but the Super Delta tail tends to have a broad base and a wide end.
With an even split at the tail base, the tail and unpaired fins should be mirror images of each other. [12] X Research source The double tail is sometimes called a ‘full-moon’ tail. [13] X Research source
The rays of a crown tail are typically long and straight, but may start to curl in response to unfavorable water conditions. [15] X Research source Crown tails may be long or short. They are typically shorter on female Bettas than male Bettas.
Betta fish that are red as juveniles may lose their coloration as adults due to the Red Loss gene. [16] X Research source For black Betta fish, the ideal coloration is pitch-black, or melano black. It is caused by a gene mutation that results in increased melanin. Melano females cannot breed eggs that will hatch, as the mutation kills the eggs. [17] X Research source Black Betta fish are usually a smoky black. [18] X Research source Some solid-colored Bettas will have a metallic look, due to pigment-containing cells called chromatophores. [19] X Research source
Butterfly Bettas have solid colors on their bodies, which partially extends to their unpaired fins. The outer edge of the fins will be a different color, creating a distinct band of color. [21] X Research source Some butterfly Bettas have three colors, and therefore do not fit the strict definition of bi-colored. The three colors will still be distinct. An example of a tri-colored Betta fish is the Thai Flag Betta (red, white, and blue). [22] X Research source Cambodian Bettas have flesh-colored bodies and deep red fins. Cambodian Bettas have lost popularity as new color patterns have been introduced. [23] X Research source
Most marbled Bettas have two colors. [26] X Research source A tri-colored marbled Betta is known as a ‘koi. ’ Koi usually have splotches of red and black on a light-colored body. [27] X Research source
Because young male Bettas do not have long fins, fin shape cannot be reliably used to determine sex in young Bettas. [31] X Research source
Male Bettas flare (open their gill covers and expand their beard) to make themselves look bigger to another male Betta. [33] X Research source
The ova may be difficult to identify in a young female Betta, making it more challenging to determine the sex. [35] X Research source
