Perhaps the main attraction to keeping and breeding betta fish is the remarkable array of dazzling colors that can be found. In this article, we take a look at the color yellow in bettas and explore the whys and wherefores of breeding fish of this vibrant, exciting color.
First of all, let’s take a simplistic look at how color works in betta fish.
When you look at a betta, what you actually see are the colors that are “on top.”
Think of each one of the betta’s scales as being a cake with many different layers. When you look at the cake from the top, you can only see the uppermost layer. Every layer controls a color. As each layer may be controlled by many different genes, the mechanism by which you can see the fish’s color becomes very complicated very quickly.
Take the color yellow as an example. To see the yellow layer, you would need to have a fish that lacked all of the other color layers, leaving the yellow layer exposed.
The whole scenario becomes even more fascinating when you consider that the different layers interact with each other. For example, a betta might appear to be light purple when it has a copper metallic layer over the top of a royal blue iridescent layer. So, now you can see why producing a pure black betta is so difficult when you know that you would have to remove all of the iridescent layer to be able to see the black!
Breeding yellow bettas
It was once thought that perpetuating the non-red betta was as simple as breeding a yellow with a yellow. Indeed, many spawns of yellow to yellow bettas do result in very high percentages, as much as 100% yellow fish in some cases, but the yellow phenotype also appears in some most unexpected places.
It would be logical to assume that an extended red fish, carrying a dominant gene, would produce more reds and extended reds. However, when breeders experimented with breeding extended red, they found that some spawns randomly threw Cambodian fish and yellow fish too.
The breeders crossed two of those yellow fish and performed an F2 mating, which yielded roughly 25% yellow bettas. The remainder of the spawn produced Cambodian red. Taking a different pair of fish from the same F1 spawn (one red and one yellow), the breeder produced roughly half Cambodian red, 40% red, and 10% yellow. Two reds from that spawn were then crossbred, with the result that 100% Cambodian red bettas were produced in the F3.
Next, one of those F3 Cambodian red bettas was outcrossed to an extended red from a different breeder’s line. The extended red was a sixth-generation red x red line fish. Prior to that, the breeder had crossed red with black/orange to get a deeper color. The result of that spawn was 40% red, 40% Cambodian red, 10% extended red, and 10% yellow.
Fascinatingly, the researchers noted that the shade of Cambodian on the Cambodian red fish from those lines was actually more yellow in color than cream or the typical flesh coloration of traditional Cambodians.
The yellow bettas produced as a result of those matings of the extended reds were not the ideal shade of yellow. Some of the fish displayed a black-scale effect that made them look dirty, while others were extremely pale. The black-scaled fish are often referred to as “Pineapples” and are produced as a result of a regular extended red fish displaying the non-red phenotype.
In an attempt to eliminate the black scale from the pineapple betta, breeders have crossed a pineapple with a red Cambodian. However, those crosses tend to produce a very pale yellow, washed-out color. So, the bottom line is that yellow is a very challenging color to work with!
Yellow does not necessarily produce yellow!
According to Dr. Gene Lucas, yellow bettas are not the result of the action of a single gene.
In fact, there is no such thing as a yellow gene that produces a yellow phenotype in betta fish. Yellow bettas are themselves phenotypes. Dr. Lucas actually designated the yellow color as “non-red”.
That non-red recessive gene was responsible for producing bettas that were yellow where they should actually be red. So, why did Dr. Gene Lucas not call the gene “yellow?”
Well, in the first place, the term “non-red” had a precedent in describing similar anomalies in other natural organisms. Also, some hobbyists may make the assumption that there was one single gene that would generate the yellow phenotype.
Furthermore, according to the official International Betta Congress (IBC) standards, yellow is considered to be a solid color, light-bodied type. Several changes must be present to produce a solid yellow color.
The black and iridocyte colors must be eliminated if possible, or at least minimized. The yellow must replace the red, and the red/yellow must be extended to cover the whole fish. That requires four separate alterations to three different pigmentation components. Two of these requirements are regulated by single-locus recessive genomes, the non-red that we previously mentioned, and the recessive Cambodian gene that pretty much eliminates dark pigment altogether.
The other two components that are the reduction of iridocyte color to minimize green or blue, if the green has been affected by yet another gene, and the extension of red to cover the whole fish, so not work as though controlled by single genes.
Research recognizes that:
- Yellow x yellow may produce Cambodian red
- Cambodian red x Cambodian red may also produce yellow
Cambodians and yellows are recessive, but they may carry each other’s genotypes.
So, in conclusion, it seems that crossing Cambodian to yellow is a good match as it should keep the yellow color as intense as possible. However, spawning yellow to yellow will eventually result in the color washing out and becoming a very pale, uninspiring yellow.