The color of Betta splendens
is based on the color pigmentation in different types of cells. These
different color cells are present in different layers within the skin.
There are basically four types of color layers in a betta with each its
own kind of color cells. In wild Betta splendens these color layers
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
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
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
- 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. Here are some examples of colors and their definitions.
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.
This is a lighter, greyish kind of blue.
Royal blue is the darkest of the three iridescent colors and sometimes
almost looks like purple.
Until now no gene has been identified that creates a complete elimination
of the blue layer. Because several breeders have bred bettas which do
not show any signs of blue, the hypothesis is there that a no-blue gene
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. The cambodian trait is
a recessive trait.
Blond bettas have a reduced density of the black pigment on the body (somewhere
half-way between cambodian and black). The mutation that is responsible
for the blond trait is recessive to the normal black gene. A Red Betta
showing the Blonde mutation exhibits a bright Red color, rather than the
usual dark "Cherry" Red.
Melano black bettas are the true black bettas. A mutated gene has caused
the black pigment to be greatly increased coverage area (melanism).
The mutated gene is recessive to the normal black gene. 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, however they are not
distinguishable from normal multicolors. These recessive characteristics
become visible in the offspring when both parents carry the mutant gene.
Because all melano females are infertile, 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 fish in the F1 generation. When breeding
to F1 generation fish together, there is a chance of getting melano blacks back in the F2 generation.
However the blacks from a pairing like this normally posses some irridescence on the body.
The 'Black Lace' betta is a dark colored fish
that rarely approaches the depth and intensity of the melano black.
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.
This type of red bettas are called extended because the normal red pigment
has increased in density and distribution. 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).
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 breeders try 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 alive and currently
many approaches are used (most of them experimental):
- Outcrossing different red lines.
- Outcrossing to Cambodian bettas.
- Outcrossing to yellow (non-red) bettas.
- Outcrossing to orange bettas.
Note: Outcrossing to cambodian, yellow and orange bettas
will result in less intense colored red offspring.
Reduced red bettas will have a darker body brownish colored body with red
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
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 . 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-red: Yellow & Orange
In non-red bettas the red pigment is replaced by yellow. This is
caused by the non-red gene (nr) which is recessive to the wildtype red (NR)
According to Dr. Gene Lucas, yellow colored bettas do not result from the
action of a single gene. 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.
Some examples of non-red fish are:
- Yellow type 1: Light type of yellow, often designated by nr1.
- Yellow type 2: Intensive colored yellow, by some breeders designated by
some breeders by nr2.
- Pineapple: These fish are the result of a normally extended red fish
showing the non-red phenotype. 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
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). 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.
The marble betta was created in the beginning of the 1970s by Orville
Gulley, a prison inmate at the penal institute in Indiana. 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.
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
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
there not more then bicolor fishes.
Unfortunately nowadays, the term mustard gas is a very
misused term. The pattern of the colors of the different MGs differ from
fish to fish. Some fish also have blue/green/black edges around their
fins while others lack these features. Most of the "modern" Mustard Gas don't
even come close to the original of Jude Als.
Because of these controversy, at 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
An opaque whites have complete white colored body and fins, with a bit of
a powdery appearance. The eyes should be black with a white border. An
opaque whites is actually an Cambodian/spread iridocyte steel blue opaque
The genetic make up of the opaque White is therefore represented by:
C bl Si Nr Op.
C - The cambodian gene for lack of dark body pigment.
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
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.
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, 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.
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.
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. 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 almost unlimited !