Color defenitions & genetics  

The color of Betta splendens is based on the color pigmentation in different types of cells [1].  There are basically four types of color layers in a betta with each its own kind of color cells. These different color cells are present in different layers within the skin. Please note that the following description of the different color layers accounts for the body only. As the finnage is much thinner the make up of the color layers probably is entirely different there. The latter still needs to be studied.

In wild Betta splendens these color layers are:
1. iridescent layer (top layer)
2. Red layer
3. black layer
4. Yellow layer (bottom layer)
In our domestic brightly colored betas the distribution of these layers is a bit different from the wildtype Betta splendens:

1. Iridescent layer (top layer):
This layer is also known as the blue layer and controls the amount of blue pigments. The iridocytes (also called guanophores), which are the blue/green cells in this layer contain the following traits:
- Iridescent colors
- Spread iridocytes
- Non-blue

2. Black layer:
The layer black layer contains melanophores or black cells which control the amount of black pigment in this layer. They contain the following traits:
- Cambodian
- Blond/Bright
- Melano

3. Red layer
The red layer contains erythrophores or red cells which control the amount of red pigment in this layer. They contain the following traits:
- Extended red
- Reduced red
- Non-red
- Variegated fins

4. Yellow layer (bottom layer)
The yellow layer contains xanthophores or yellow cells. So, far no genes have identified that control the yellow layer of pigmentation.
- The absence of the red layer, black layer and iridescent/blue layer.

Each of these color layers has its own genetic code which is determined by series of genes which combined eventually determine the color of the betta. The different genes either increase of decrease the pigment in the different layers. In this chapter I will try to explain something more about these different traits.


Iridescent colors: Turquoise, Steel and Royal blue
Turquoise, steel and royal blue are called the three iridescent colors. Iridescent colors make up the top layer of the betta and are caused by cells called iridocytes. These cells form a dense color layer which can cover all other colors. Originally, on wild Betta splendens the normal iridescent color is turquoise/green. This normal iridescence (represented by genotype sisi is limited to ray-like projections into the fins and several iridescent dots along the body of the fish.


Selective breeding gave rise to a mutated iridescence gene which lead to spread iridescence (represented by genotype SiSi). The Si gene is responsible for the increase in density and distribution of the iridescent color so that it covers the entire body and fins of the betta (with exception of the head). The spread iridescent gene is dominant to the normal (wildtype) iridescent gene.


The best way to describe turquoise is, a color between blue and green.

Steel blue
This is a lighter, greyish kind of blue.

Royal blue
Royal blue is the darkest of the three iridescent colors and sometimes almost looks like purple.

Turquoise HM male [5]
Steel blue HM male [5]
Royal blue HM male [5]
A turquoise betta is represented by: BlBl
A steel blue betta is represented by: blbl
A royal blue betta is represented by: Blbl

Turquoise and steel are not dominant over each other.
Both colors interact to produce a blending of the two colors into a new color: royal blue.
This type of inheritance is called intermediary dominance.
      turquoise x turquoise   steel blue x steel blue   royal blue x royal blue      
      100% turquoise (BlBl)   100% steel blue (blbl)   25% turquoise (BlBl)
50% royal blue (Blbl)
25% steel blue(blbl)
      turquoise x steel blue   turquoise x royal blue   steel blue x royal blue      
      100% Royal blue   50% turquoise (BlBl)
50% royal blue (Blbl)
  50% royal blue (Blbl)
50% steel blue (blbl)

Until now no gene has been identified that creates a complete elimination of the blue layer [1]. Because several breeders have bred bettas which do not show any signs of blue, the hypothesis is there that a no-blue gene exists.
However in the case of a blbl (steel blue) combined with sisi (normal iridescence) the blue layer could be very limited an only give a small silver glow. A betta with this genotype would probably not be recognized as an actual blue.


The best example of a cambodian is the traditional or red cambodian which has red colored fins and a flesh colored body (but there are also blue cambodians). The cambodian gene causes a fish to have colored fins and colorless or greatly reduced color on the body [2]. The cambodian trait is a recessive trait.

Cambodian DT male [7]
Cambodian Butterfly Delta male [7]
A cambodian betta is represented by: cc
A normal betta is represented by: CC
A cambodian-geno betta is represented by Cc
      Cambodian x normaal   Cambodian-geno x Cambodian-geno      
      100% Cambodian-geno (Cc)   25% Cambodian (cc)
50% Cambodian-geno (Cc)
25% Normal (CC)
      Cambodian x Cambodian-geno   Cambodian x Cambodian      
      50% Cambodian (cc)
50% Cambodian-geno (Cc)
  100% Cambodian (cc)      

Blond bettas show a reduced density of black pigment on the body (between cambodian and black). The mutation that is responsible for the blond trait is recessive to the normal black gene. Some colors like pastels, yellows and opaques are  associated with the blond gene [17]. But the blond gene can also be found in combination with other colors like black, steel blue and red. Blonde steels will appear silver, blonde blacks will look washed out and pale and blonde reds exhibit a bright Red color, rather than the usual dark "Cherry" Red.

Blonde red HM male [18]
Blonde red HM male [10]

Melano black
Melano black bettas are the true black bettas. A mutated gene has caused the black pigment to be greatly increased coverage area (melanism) [3].

Melano HM male [6]
Magnificent melano HM male [20]
Steel blue (melano-geno) HM male [5]
A melano black betta is represented by: mm
A normal betta is represented by: MM
A melano black-geno betta is represented by: Mm

The mutated gene (m) is recessive to the normal black gene (M). This means that when a melano black betta is spawned to a normal betta that does not have the mutated black gene, all offspring would look like multicolored bettas. These offspring are carrying the gene for melanism and are called melano-geno (Mm), however they are not distinguishable from normal multicolors. These recessive characteristics become visible in the offspring when both parents carry the mutant gene.
The melanophores from melanos grow very differently from that seen in black lace and wild type [18]. They pile up and are very sticky, which is why they produce such a dense black. Melanos have a lot of speckling throughout their fins that that make them look so dark, these are actually 'balls' of melanophores. Preliminary studies have shown that these melanophores have extra adhesion proteins. One hypothesis is that these proteins are also responsible for female infertility. Melano females will produce eggs during the act of spawning like a normal female, but something happens during the hatching process that causes the fertilized egg to rupture.

      Melano black x normal   Melano black x melano-geno      
      100% melano black-geno (Mn)   50% Melano black (mm)
50% Melano black-geno (Mm)
      Melano-geno x melano-geno   Melano black x melano black      
      25% Melano black (mm)
50% Melano black-geno (Mm)
25% Normal (MM)
  100% Melano black (mm)      

Because allmost all melano black (mm) females are not fertile, mostly blue females are used to breed melano blacks. Preferably steel females are used because these females posses the least irridescense of all blues. A pairing like this, produces melano-geno (Mm) fish in the F1 generation. When breeding to F1 generation fish together, there is a chance of getting melano blacks (mm) back in the F2 generation. However the blacks from a pairing like this always posses some irridescence on on the body.
There are several reports of melano marble and melano copper females being normally fertile and can be normally used for breeding.


Black lace
The 'Black Lace' betta is a dark colored fish that rarely approaches the depth and intensity of the melano black [18]. Most Black Lace fish display too much iridescence in body and fins to be competitive in the black class, and are instead shown into the dark bicolor class. Most black lace fish we see today come out of marble strains. It is thought that first black lace colored fish arose from Oriental non-red stock.
The ends of the fins of black lace fish should be clear or cellophane in color, causing the 'lacy' look that gave this type of black its name. Amateur hobbyists in particular need to be careful not to confuse black lace with melano butterfly, the fins of which can also fade to clear or smoke. Unlike the black lace, the melano butterfly will still maintain a very dark black or blue-black body color, and are still genetically melanos. Like melano black, black lace is recessive to normal dark color. Unlike melano, black lace female are normally fertile.

Black lace HM [21]
    Extended red
This type of red bettas are called extended because the normal red pigment has increased in density and distribution [3,8]. The red color is spread over the entire body and fins of the fish on a similar way like the spread iridescence (Si) gene for the iridescent colors. The extended red (Er) mutation is dominant over the gene for normal red color (R).
Extended red HM male [20]
Extended red HM male [9]
Extended (blond) red HM male [18]

Ideally the extended red betta should carry no iridescence and no black scales. Most extended red lines carry some degree of iridescence. This due to the fact that many breeder tried to improve the finnage of their red line by outcrossing to superfinned iridescent lines. The red is then bred back from these lines but the iridescence is hard to loose.
The quest for the perfect extended red betta is still going on and there are many approaches which are followed to achieve this goal (most of them experimental):
- Outcrossing different red lines.
- Outcrossing to cambodian bettas.
- Introducing the blonde gene
- Outcrossing to yellow (non-red) bettas.
- Outcrossing to orange bettas.
Note: Outcrossing to cambodian, yellow and orange bettas most of the time will result in less intense colored red offspring.


Red loss
The red-loss trait will cause the red color in young bettas to disappear when it matures. When the fish ages or due to fin damage, the red color sometimes returns.
It is thought that the red-loss mutation was introduced together with the marble mutation (see below), because most marbles do not show any red pigment [3].

Red female before red loss [10]
Red female after red loss [10]

The red-loss trait is caused by distinct gene than the marble gene (which affects the black coloration), the red-loss (Rl) gene. The red-loss mutation is extremely variable in its expression and is dominant over all other Red genes, except extended red.


Non-reds: Yellow & orange
Non-red is believed to be a mutation of the red gene. The non-red gene (nr) is recessive to the wildtype red (NR) gene. Two varieties of the non-red gene are known: yellow (nr1) and orange (nr2).


According to Dr. Gene Lucas, yellow colored bettas do not result from the action of a single gene [8]. There is no such thing as a yellow gene that produces a yellow phenotype in Bettas. Yellow Betta are phenotypes. The yellow color itself was designated as 'non-red' by Lucas. This 'non-red' recessive gene caused bettas to be yellow where they would normally be red. The reason why Dr. Gene Lucas did not call the gene yellow was:
1. The term non-red had been used previously to describe similar abnormalities in other organisms.
2. To avoid having people making the assumption that there was a single gene that would generate the yellow phenotype.

Yellow type 1 HM male [5]
Yellow (type2) BF HM male [9]
Pineapple plakat HM male [13]

Some examples of non-red yellow fish are:
- Yellow type 1: Light type of yellow
- Yellow type 2: Intensive colored yellow [9].
- Pineapple: These fish are the result of a normally extended red fish showing the non-red phenotype [8]. Pineapples are not clean yellows because they show black-scaling.


Orange bettas are relative new development. The nr2 gene causes a more of a red/yellow (orange) color. A very deep, pumpkin orange with minimal black scale effect is desired. Orange isn't an easy color to maintain. It is has been reported that over time spawns of orange x orange can become washed-out in appearance.
Regular outcrossing to black-orange lines might help to maintain the intensity.

Orange HM DT male [6]


Orange HM male [15]

Variegated fins (butterfly)
Some butterflies only show a small clear band around the fins while others have allmost completely clear fins. But there are many degrees of the butterfly pattern between these two extremes. The ideal butterfly pattern shows an equal division between color and clear fins.
The butterfly patterns is caused by a mutated gene called variegated fins (Vf) [3]. The variegated fin mutation is dominant but the effects of this mutation are, as mention before, highly variable from fish to fish.
Note: When a betta carries the butterfly pattern and is melano carrier the clear edges can also be black colored.

Blue butterfly HM male [5]
Red butterfly DT male [11]
Blue butterfly DT male [5]

The marble betta was created in the beginning of the 1970s by Orville Gulley, a prison inmate at the penal institute in Indiana [3, 8]. Orville as breeding betta here in peanut butter jars, as part of a rehabilitation program. The story goes that Orville was trying to create a black butterfly betta which then led to the discovery of the marble gene. Walt Maurus and a handfull of other breeders started to breed the marbles for pattern and this lead to the distrubution of the marbles all over the United States. The orginal marbles were black and white but now they are available in virtually every color imaginable.

Blue marble Butterfly HM male [5]
Black/white marble DT male [11]

In young marbles bettas the marble pattern can shift from week to week and once the fish matures most of the times the pattern is fixed.
The marble mutation appears to be a partly dominant gene, the marble (Mb) gene, which has a highly variable expression. When marbles are introduced into a true-breeding solid colored line, it is becomes very difficult for the breeder to return his stock to a non-marble true-breeding solid colored type.


Mustard gas
The Mustard gas was created by Jude Als (Unkle Junkin). The original Mustard gas bettas had a solid blue/greenish body and yellow fins. Because this line bred true Jude Als thought of this strain name, but actually they are not more then blue/yellow bicolor fishes.

Orginal Mustard gas delta male [12]
Mustard gas HM male [11]
Mustard gas HM male [9]

As you can see on the pictures above, nowadays, the term mustard gas is a very plastic term. The pattern of the colors of the different MGs differs from fish to fish. Some fishes also have blue/green/black edges around their fins while others lack these features. Most of the "modern" Mustard don't even come close to the original of Jude Als.
Because of these controversy, on shows mustard gas bettas are classified into the bicolored class.


Chocolate Bettas as they are commonly called, have a brown body with yellow fins. But actually they are black/Yellow bicolor bettas.
Chocolates are often bred to yellow in order to improve the color of both lines. On shows like mustard gas bettas, chocolates are classified into the bicolored class.

Chocolate HM male [5]
Chocolate HM male [14]

Opaques were created by Dr. Gene Lucas. To be correct opaque itself isn't a color but a trait which is characterized by a thick powdery appearance. The opaque (Op) factor is inherited by intermediate (partial) dominance.
Opaque does not necessarily mean white, there are actually three types; steel blue, green and blue (royal blue) opaques. Opaque whites are actually steel blue opaques. Green and blue opaques have a green or blue sheen instead of pure white colour.

The genetic make up of a opaque white
is represented by: C bl Si Nr Op [1].
C - The cambodian gene for lack of dark body pigment which causes the light body.
bl - Steel blue pigment which appears silvery-white when on a light background.
Si - The spread of the iridocyte pigment, in this case steel blue over the fish.
Nr - Non-red, causes the inability to produce red pigment.
Op - Opaque, the special gene that cause the powdery appearence of the fish.

Note: It is also possible for opaques to arise as a result of marble genes. In order for that to happen off course the steel iridescence and the opaque factor must be present.

The I.B.C. judging standards define this breed (Opaques) as: Non-Red light bodied fish similiar in appearance to Pastels. However, there are guanine deposits giving a denser milkier appearance and an opacity to the coloration of these fish. These deposits are most visible around the head and eye and continue to accumulate as the betta ages.

Opaque white HM male [5]

Opaque white DT male [5]

The thick powdery "white" pigment is the key to distinguish an opaque and a pastel betta. This can most easily be observed by looking at the fish from above and around the head.
The genetic make up of a pastel is C Bl Si Nr.
C - The cambodian gene for lack of dark body pigment which causes the light body.
- Steel blue pigment which appears silvery-white when on a light background.
- The spread of the iridocyte pigment, in this case steel blue over the fish.
- Non-red, causes the inability to produce red pigment.
(Op Opaque, optional but necessary to a degree. If too littely opaque factor, the fish appear translucent, and if too much, they may be classified as Opaques).
Note: To be entirely correct opaques are actually also pastels with the only difference that opaques carry much more opaque factor than pastels.

Some pastels [3]

Pastels are iridescent bettas (blue, steel blue and green). It is the (C) cambodian or non-red gene that differentiates them from the regular dark body iridescent bettas. Pastels are homozygous for cambodian, which gives them the light flesh coloured body. Most Pastels also carry a little opaque factor to give the iridescent appear more solid. Without the opaque factor, the iridescent color would be translucent in the absence of dark pigment (black or red).


Copper & Mask
The now so popular copper color and "mask" characteristic are both developments which were created by crossing Betta splendens to Betta mahachai and/or Betta imbellis.
The latter two species naturally have a higher degree of iridescence on the scales to compensate for the murkier waters of their native lands [8].
Outcrossing these species to betta splendens and selective breeding resulted in  true breeding hybrid plakat bettas which were called 'copper imbellis'. These fish possessed two new features; (1) metallic scaling and (2) masking.

Copper imbellis male [22]

By selective breeding, the Asian breeders succeeded to develop the copper imbellis into a longfinned line and selectively breeding lead to a heavy and thick metallic/copper color and a masking which was more or less covering the head.
The typical metallic/copper sheen is caused by the crystalline layer. Whereas in classic blue-green the iridophores are all the same size and shape, metallic iridophores are characterized by different shapes and sizes. Because of this the crystaline layer influences the refraction of the light spectrum which could be an explaination for the color changes which sometimes can be observed in metallics.


The copper/metellic color and the "mask" characteristic are distinct traits which both are inherited by intermediate (partial) dominance. Crossing copper to a normal blue (non-metallic) will give metallic blues in the first generation (F1) with a chance of getting copper back in the next generation (F2). The same accounts for the mask characteristic. When a full mask fish (homozygous mask) is paired with a non-masked fish this can lead to heterozygous mask offspring (F1). Keep in mind here that the degree of masking will greatly differ in the offspring, some will show some masking while other don't show it. The next generation (F2) will give you fish with more masking signs or maybe even some full masks. I think selection also plays a great role here.
Still a lot of experimenting can be done with these relavitely new traits. These traits can be combined with other colors like blue, melano, opaque, red, yellow, etc. Both traits influence all other colortypes and the possibilities seem allmost unlimited!

Copper/gold HM PK male

Copper/gold HM male [5]
Metallic green HM male [9]
Platinum white DT male [6]
Copper/black lace CT male [14]
Red/gold HM male [16]
Red copper "Brass" HM male [8]

The first dragons arose few years after the metallic mutation had established itself in the betta hobby. Dragons are characterized by an exceptional thick iridescence on the body. The exact origin of this trait is not known but like metallics, there is a good chance dragons originate from outcrossing to wild bettas.
The main difference between metallics and dragons lies in the development of the iridescence in young fish. With metallics the defenite color is already visible in an early stage of development (~2 months of age), but with dragons the iridescence becomes thicker and thicker as the fish matures.
These dragon trait can be combined with many other colors and more knowledge on this trait still has to be collected on its genetic behavior.

Red dragon male [22]
Yellow dragon male [23]
Red dragon male [24]

1. Betta onli
2. Betta bunnies
3. Betta by Jim Sonnier
4. Artesian Bettas
5. Sarawut Angkunanuwat (Siamimbellis)
6. Teeruch Poparnich (Xmanbettas)
7. Thomas Nguyen
8. Victoria Parnell (Bettysplendens)
9. Lapheng Xiong (Topbettas)
10. Myron Tay
11. Marianne Lewis (BCbetta)

12. Jude Als (Unkle Junkin Champion Bloodlines)


13. Xavier Tan
14. Marcel van den Bossche (Magicbetta)

15. Suporn Khumhom (Bluebetta)
16. Chok Pengdit (Suthasine betta)
17. Jeff Wilson
18. Peter Goettner
19. Mark Ibara
Markus Gutzeit and Rajiv Massilamoni

21. Atison Phumchoosri (Atisonbetta)
22. Dong
23. Interbettas
24. Black_knight

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