Known Genetics

BETTA GENETICS

Wild type Bettas exhibit four color pigments; Black, Red, Yellow, and Iridescents (metallic Blues and Greens). The arrangement of these colors creates a Betta with the well known pattern that we call Multicolor. The Yellow color is so much less dense than all other colors and is, by nature, such a light color that it can be safely ignored in a discussion of Betta color genetics. But do not confuse this wild type Yellow with the Yellow that we find in our domestic "Non-red" Yellows and Bicolors. The bright Yellow color that we see on our domestic Bettas is actually Red pigment that has been altered by genetic mutation. I will write about the known genetic mutations that affect Black, Red, and Metallic pigmentation in Bettas. Each normal color can be genetically manipulated in five basic ways. It can be reduced, absent, altered, extended, or patterned.

BLACK COLOR IN BETTAS

In wild type Bettas Black is a color that is often covered by other colors. The distribution of Black pigment is all over the fish except for most of the caudal fin and the abdomenal area. This dispersion is of medium density but is not usually obvious because of other overlying colors.

BLACK BETTAS are also called Melanos. A mutant gene has caused the Black pigment to be greatly increased in density and coverage area. The overall appearance of these Bettas is quite Black. The mutated gene that causes increased Black color in Bettas is recessive to the normal Black gene. This means that if a Melano Betta were spawned to a normal Betta that does not have the mutated Black gene all the offspring would look like Multicolored Bettas. These offspring would be carrying the gene for melanism but it would not show in their coloration. These Bettas would be called Black genotypes and would be indistinguishable from normal Multicolors. Recessive characteristics only become visible if both parents pass down the mutant gene to their offspring. Some representative spawning results are presented below...


Male Parent Female Parent Offspring
Black Red 100% Multicolor(Black genotype)
Black Multicolor(Black genotype) 50% Black 50% Multicolor(Black genotype)
Black Black (Black females are infertile)
Multicolor(Black genotype) Blue 100% Multicolor(50% Black genotype)
Multicolor(Black genotype) Multicolor(Black genotype) 25% Black, 75% Multicolor(67% Black genotype)

CAMBODIAN BETTAS are Bettas with cream or white colored bodies. This mutant was first discovered in the country of Cambodia. In this case the mutation causes an absence of Black pigments on the fish. Other colors such as Red, Yellow, and Blue or Green may be present. The fins are not as affected as the body but the fin coloration is lighter than that of normal dark-bodied Bettas. Like the gene for Melano the Cambodian gene is also recessive to the normal Black gene.

Male Parent Female Parent Offspring
Cambodian Green (dark bodied) 100% Multicolor(Cambodian genotype)
Cambodian Multicolor(Cambodian genotype) 50% Cambodian, 50% Multicolor(Cambodian genotype)
Cambodian Cambodian 100% Cambodian
Multicolor(Cambodian genotype) Red (dark bodied) 100% Multicolor(50% Cambodian genotype)
Multicolor(Cambodian genotype) Multicolor(Cambodian genotype) 25% Cambodian, 75% Multicolor(67% Cambodian genotype)

BLONDE BETTAS have faded or washed out colors due to a mutant gene that has caused the Black pigment to be significantly reduced in density. The overall appearance of Blonde Bettas is pale with a lack of color contrast. A Red Betta showing the Blonde mutation exhibits a bright Red color, rather than the usual dark "Cherry" Red. The mutated gene that causes the Blonde characteristic is also recessive to the normal black gene. Betta breeders have not shown much interest in the Blonde mutation for obvious reasons.

MARBLE BETTAS are Bettas with Black pigment of variable density on different parts of the body and fins, much like the coloration of a painted horse. The individual densities range from areas of no Black color all the way to very dark Black areas. When these Bettas are young the patterns of Black on white seem to shift and change from week to week. Once the fish has reached maturity the pattern is well fixed and there is usually little change from that point on. This Marble mutation appears to be a dominant gene with highly variable expression. When Marble Bettas are spawned the offspring are usually of several types including Cambodian, Blonde, Black, and Marble.

Marble Bettas were revived in America by Orville Gulley at the beginning of the 1970's. He was an inmate at a penal institution in Indiana. Walt Maurus, the number one spokesman for the Betta hobby at that time, supplied Mr. Gulley with fish and supplies through a prison rehabilitation program. When the Marbles were ready Walt distributed them to many serious breeders throughout the United States.

RED COLOR IN BETTAS

In wild type Bettas Red is a layer of color that is just above the Black layer. The only other colors that can cover Red are the Iridescent Blues and Greens. The distribution of Red is limited to the pelvic, anal, and caudal fins. The color density is usually heavy in those areas. The normal distribution of Red color can easily be seen on most Multicolor Bettas.

RED BETTAS are also called extended Red because the normal Red pigment has been increased in density and extended in distribution to cover the entire body and fins of the fish. This mutant gene causes the Betta to appear to be solid Red in color. These are the brilliant Red Bettas that are so popular with fish keepers and breeders. The extended Red mutation is dominant over the gene for normal Red color. Some representative spawning results are presented below...

Male Parent Female Parent Offspring
extended Red Multicolor 100% extended Red
extended Red extended Red 100% extended Red

YELLOW BETTAS are also called Non-red Bettas. This mutated gene causes the formation of Yellow pigment instead of Red, or we can say that the Red pigment has been altered to Yellow. This mutation affects both normal Red and extended Red coloration. A Yellow (non-Red) Betta will have no Red pigment anywhere on the fish. The non-Red mutation is recessive to the gene for normal Red color. Some representative spawning results are presented below...

Male Parent Female Parent Offspring
non-Red(Yellow) Multicolor(normal Red) 100% Multicolor(non-Red genotype)
non-Red(Yellow) Multicolor(non-Red genotype) 50% Multicolor(non-Red genotype), 50% non-Red(Yellow)
Multicolor(non-Red genotype) Multicolor(non-Red genotype) 75% Multicolor(67% non-Red genotype), 25% non-Red(Yellow)
non-Red(Yellow) extended Red 100% extended Red(non-Red genotype)
non-Red(Yellow) non-Red(Yellow) 100% non-Red(Yellow)

RED-LOSS Bettas could also be called single-colored Bettas. Aside from their beauty the Marbles brought with them another important mutated gene that has impacted nearly all other colors of Bettas. It was noted early that most Marble Bettas did not have any Red pigment, not even in the pectoral fins and gills. I believed that a separate mutant gene (other than the Marble gene that affects Black coloration) was responsible for this absence of Red. I named this gene the Red-loss gene because the Red color found on most young Marbles seemed to disintegrate and disappear as they grew. Sometimes the loss of Red pigment stopped at some point during this process, but often it continued until the Betta was completely devoid of all Red color. These Bettas that had lost all their Red pigment were the best Marbles. By crossing these fish into Cambodian Blues and Greens I was able to produce some beautiful Pastels (see photo). The next step was to produce dark-bodied Blues and Greens that showed the effects of the Red-loss gene. Black Bettas received the Red-loss mutation in their turn. All of these new Red-loss Bettas were superior show fish, since they did not have Red faults to detract from their point totals at shows. The Red-loss mutation is extremely variable in its expression and is dominant over all other Red genes, except extended Red. Some representative spawning results are presented below...

Male Parent Female Parent Offspring
Red-loss Multicolor high% Red-loss
Red-loss extended Red ?Red Marbles?

BUTTERFLY BETTAS are Bettas that have the mutant gene that causes variegated fins. The first color affected by this mutation was Red, but now Butterflies can be found in most of the other colors as well. Some Butterflies have fins that are almost totally Red except for the edges. Other Butterflies have almost completely Clear fins. There are Butterflies of all degrees in between. The ideal Butterfly pattern shows an equal division between Red and Clear on the fins. The variegated fin mutation is dominant but the effects are highly variable from fish to fish. Usually a spawning will produce a few outstanding Butterflies and many that do not have a very good pattern. To develop a Betta strain with the perfect Butterfly pattern would be a notable accomplishment for any breeder!

IRIDESCENT COLOR IN BETTAS

In wild type Bettas Iridescent color (Blues and Green) is the densest layer that can cover all other colors. The normal distribution of Iridescent color is limited to ray-like projections into the fins and several rows of Iridescent dots along the body of the fish. The color density is usually very heavy in those areas. The normal Iridescent color on wild Bettas is Green.

GREEN BETTAS are also called Turquoise because the color usually has a Blue tint. The mutated gene has been named spread Iridescence because the normal Green pigment has been increased in density and extended in distribution to cover the entire body and fins of the fish. This mutant gene causes the Betta to appear solid Green in color except for the head area. The mutation for spread Iridescence is dominant to the normal Iridescent gene. Some representative spawning results are presented below...

Male Parent Female Parent Offspring
spread Iridescence normal Iridescence 100% spread Iridescence
spread Iridescence spread Iridescence 100% spread Iridescence

STEEL BLUE BETTAS are produced by a color mutation gene. The normal Green color is altered and appears as a Steel Blue color instead of Green. This color mutant affects both the normal Iridescent distribution and the spread Iridescent distribution. This means you can have solid Steel Blue Bettas if you combine this color mutation with the spread Iridescence mutation. Neither the normal Green gene nor the mutated Steel Blue gene is dominant over the other. These genes interact to produce a blending of the two colors into a new color. This prime example of intermediate dominance produces Blue (also called Royal Blue) coloration. Simply put, this means that a Green Betta possesses two normal Green genes, a Steel Blue Betta possesses two mutated Steel Blue genes, and a Blue Betta posses one normal Green gene and one mutated Steel Blue gene.

BLUE BETTAS are also called Royal Blue Bettas. As stated above these fish have one normal Green gene and one mutated Steel Blue gene which combine to produce an intermediate Blue color. Many feel that this is the most beautiful Iridescent color. Some find it difficult to comprehend that a spawning between a Green and a Steel Blue will produce only Blue offspring, but it is true. Some representative spawning results for the three Iridescent colors are presented below...

Male Parent Female Parent Offspring
Green Green 100% Green
Green Blue 50% Green, 50% Blue
Steel Blue Steel Blue 100% Steel Blue
Steel Blue Blue 50% Steel Blue, 50% Blue
Steel Blue Green 100% Blue
Blue Blue 25% Green, 50% Blue, 25% Steel Blue

FINNAGE VARIATIONS IN BETTAS

In wild type Bettas normal finnage is short somewhat like our domestic females, only a little more angular and pointed. All other finnage types are mutations that affect the original short fins. Some of these mutant genes are inherited as simple dominants, while others appear to be sex influenced or cumulative multiple pairs.

LONG FIN BETTAS are also called Veiltails and they are the kind you find at your local pet store. The male's tail is elongated and droops downward. This type of tail is graceful and beautiful in its own right. This mutation also causes the other fins to be elongated and larger than the normal wild type short fins. The Long Fin mutant is dominant over Short Fin.

DOUBLETAIL BETTAS are produced by another mutant gene that causes the caudal (tail) fin to be divided into two lobes. A secondary characteristic produced by this mutation is a tremendously enlarged dorsal fin. The Doubletail dorsal is many times wider than the dorsal on a Singletail Betta. In fact, the dorsal and anal fins on Doubletail Bettas appear to be about the same size and width. The mutation that causes Doubletail traits in Bettas is recessive to the normal Singletail. Some representative spawning results for the Long Fin and Doubletail genes are presented below...

Male Parent Female Parent Offspring
Short Fin Long Fin 100% Long Fin (Short Fin genotype)
Short Fin Long Fin (Short Fin genotype) 50% Long Fin (Short Fin genotype), 50% Short Fin
Long Fin Doubletail 100% Long Fin (Doubletail genotype)
Long Fin (Doubletail genotype) Long Fin (Doubletail genotype) 75% Long Fin (67% Doubletail genotype), 25% Doubletail

DELTATAIL BETTAS are a result of selective breeding and have roughly straight edges on each side of their tails. The degree of the tail span can be anywhere from about 120 degrees to near the Half Moon's 180 degrees. It does not appear that any single gene is responsible for this tail shape, but rather a combination of factors, both genetic and environmental. The deltatail shape is one of the most beautiful and durable in Bettas. Even in old age these fish maintain a pleasing and regal appearance.

CROWNTAIL BETTAS appear to have been perfected in the East; Thailand, Singapore, and China. The rays of the fins and tail extend out past the webbing, giving some of these fish a somewhat startling appearance. (note: actually the rays appear to be of normal length and the webbing appears to be reduced) Some fish show rays that extend very far past the webbing - even 50% of the tail length. Some fish show branching that causes a single ray to have 2, 4, 8, or even 16 ray tips. There is even a variety that has crossed rays. Some people say they are outstanding while others say they look more like insects than fish.

HALF MOON BETTAS were created during the last 10 years by European breeders. The most outstanding characteristic of Half Moons is the half circle caudal (tail). The edges are straight - one straight up and the other straight down. The rays and webbing then form a perfect 180 degree half circle around to the forward facing edges. In the ideal Half Moon Betta the dorsal and anal fins are also somewhat modified and together with the caudal all fin edges form a circular pattern approximately two thirds of the way around the body. Another key characteristic of the Half Moons is extra ray branching particularly in the caudal. In normal Bettas the caudal rays branch once, maybe twice in better fish. But in Half Moons the caudal rays branch a third time in the best fish, or even a fourth time . That means a single ray starting from the caudal peduncle can end up with 16 ray ends at the edge of the tail. An important consideration when working with Half Moons is the fact that they do not breed true. From Half Moon parents you may get no Half Moon offspring, or only one or two. Typically you will get less than 10% Half Moon offspring. With careful observation and much hard work these dedicated Betta breeders have created a magnificent new form for all of us to admire and enjoy.

My research and experience with Half Moons leads me to believe that there are at least 3 genetic factors required to produce a Half Moon Betta. First, all caudal rays must be perfectly straight with no curving or bending. Second, the straight caudal rays must branch multiple times with triple branching producing the best fish. Third, extra spread in the webbing between the rays allows the 180 degree caudal fan to form. It appears that the straight rays and the extra webbing spread are heavily impacted by environmental factors. Even if the Betta possesses these genetic traits they may not show because of generally poor water conditions or bad rearing techniques.

If all three of these genetic factors were inherited as recessives (or all three as dominants) then Half Moon Bettas would breed true and you would get 100% Half Moon offspring from a mating of Half Moons. So it seems safe to say that the three genetic factors are a mixture of dominant and recessive traits. My guess would be that the gene for multiple branching is a dominant trait, while the genes for straight rays and extra webbing spread are probably recessive traits. If this hypothesis is correct then only 3 fish out of every 64 offspring from heterogeneous parents would have the required genetic material to become Half Moons, and 2 of those 3 would be heterozygous (not pure) for multiple branching. Then there is the problem of lower quality environmental conditions inhibiting the actions of the Half Moon genes. My overall conclusion is that raising Half Moons is extremely difficult and the numbers of Half Moons produced will quite likely be very small.

GIANT BETTAS

At the Orlando IBC Convention in June, 2002 several very large Bettas were shown in class G4, Form and Finnage. There were two about 7 inches long and three or four about 3.5 inches long. Gene Lucas called the larger ones, "Two-pounders!" A couple were long-finned but most of them were short-finned Plakats. The picture above shows the 4.5 inch one I purchased at the auction after the show.

I spawned him to a regular sized Plakat female (spawn#111002) and was rewarded with about 50% Half-Giants (3.5 inch) and about 50% regular sized offspring. Some photos of the offspring can be seen here.

Interestingly some of the Half-Giant offspring showed early rapid growth while only a couple looked normal until about 8 months of age and then had a growth spurt to Half-Giant size. All, however, had voracious appetites and ate much more food than their regular sized siblings.

Based on my limited observations to date I am thinking that the Giant condition is controlled by a single pair of mutated genes. It appears that offspring receiving both Giant genes from their parents should grow to about 7 inches in length. And it follows that heterogeneous offspring receiving only one Giant gene from their parents should grow to a length of about 3.5 inches. See the table below for expected results from spawnings with Giant Bettas.

Male Parent Female Parent Offspring
Giant(7") Giant(7") 100% Giant(7")?
Giant(7") Half-Giant(3.5") 50% Giant(7"), 50% Half-Giant(3.5")?
Regular Size(2+") Half-Giant(3.5") 50% Regular Size(2+"), 50% Half-Giant(3.5")
Half-Giant(3.5") Half-Giant(3.5") 25% Giant(7"), 50% Half-Giant(3.5"), 25% Regular Size(2+")?

Info provided by Jim Sonnier's website: http://www.bettas-jimsonnier.com