Wild fish exhibit strong colours only when agitated.
Breeders have been able to make this coloration permanent, and a wide variety of hues breed true.
Colours available to the aquarist include red, orange, yellow, blue, steel blue, turquoise/green, black, pastel, white ("opaque" white, not to be confused with albino) and multi-coloured fish.

Bettas are found in many different colours due to different layers of pigmentation in their skin.
The layers (from furthest within to the outer layer) consists of red, yellow, black, iridescent (blue and green), and metallic (not a colour of its own, but reacts with the other colours to change how they are perceived).
Any combination of these layers can be present, leading to a wide variety of colours.

The shades of blue, turquoise, and green are slightly iridescent, and can appear to change colour with different lighting conditions or viewing angles; this is because these colours (unlike black or red) are not due to pigments, but created through refraction within a layer of translucent guanine crystals.
Breeders have also developed different colour patterns such as marble and butterfly, as well as metallic shades through hybridization like copper, gold, or platinum (these were obtained by crossing B. splendens to other Betta species).

A true albino betta has been feverishly sought since one recorded appearance in 1927, and another in 1953.
Neither of these was able to establish a line of true albinos.
In 1994, a hobbyist named Kenjiro Tanaka claimed to have successfully bred albino bettas.

Some bettas will change colours throughout their lifetime (known as marbling), attributed to a transposon.

Koi bettas have mutated now and some are no longer marbles and do not change colors or patterns through out their lifetime (known as true Koi) attributed to the defective gene that causes marbling not being repaired in the color layers after a time.

Common Colours
Super Red
Super Blue
Super Yellow
Opaque
Super Black
Super White
Orange
Marble
Candy
Nemo
Galaxy Nemo
Koi
Alien
Copper
Cellophane
Gold
Galaxy Koi
Rarer Colours
Super Orange
Metallic
Turquoise
Lavender
Mustard Gas
Grizzle
Green
Wild fish exhibit strong colours only when agitated. Breeders have been able to make this coloration permanent, and a wide variety of hues breed true. Colours available to the aquarist include red, orange, yellow, blue, steel blue, turquoise/green, black, pastel, white ("opaque" white, not to be confused with albino) and multi-coloured fish.
Bettas are found in many different colours due to different layers of pigmentation in their skin. The layers (from furthest within to the outer layer) consists of red, yellow, black, iridescent (blue and green), and metallic (not a colour of its own, but reacts with the other colours to change how they are perceived). Any combination of these layers can be present, leading to a wide variety of colours.
The shades of blue, turquoise, and green are slightly iridescent, and can appear to change colour with different lighting conditions or viewing angles; this is because these colours (unlike black or red) are not due to pigments, but created through refraction within a layer of translucent guanine crystals. Breeders have also developed different colour patterns such as marble and butterfly, as well as metallic shades through hybridization like copper, gold, or platinum (these were obtained by crossing B. splendens to other Betta species).
A true albino betta has been feverishly sought since one recorded appearance in 1927, and another in 1953. Neither of these was able to establish a line of true albinos. In 1994, a hobbyist named Kenjiro Tanaka claimed to have successfully bred albino bettas.
Some bettas will change colours throughout their lifetime (known as marbling), attributed to a transposon.
Koi bettas have mutated now and some are no longer marbles and do not change colors or patterns through out their lifetime (known as true Koi) attributed to the defective gene that causes marbling not being repaired in the color layers after a time.
Common Colours
Super Red
Super Blue
Super Yellow
Opaque
Super Black
Super White
Orange
Marble
Candy
Nemo
Galaxy Nemo
Koi
Alien
Copper
Cellophane
Gold
Galaxy Koi
Rarer Colours
Super Orange
Metallic
Turquoise
Lavender
Mustard Gas
Grizzle
Green
Siamese fighting fish