Betta Genetics

One popular question many people ask when breeding bettas is "What will I get when I breed a (insert tail type/color) with a (insert another tail type/color)?" Instead of answering the question without really explaining why or how, I'll teach you how to determine what the offspring will look like. Just like the Saying goes "Give a man a fish and you feed him for a day. Teach a man to fish and you feed him for a lifetime." (how ironic, its about fish too).

Before we get started heres some important vocab words that will help you better understand.

The one main rule for genetics is that if the trait is dominant, then it will show even if the genotype has a recessive gene in it. If the genotype has at least 1 gene for a dominant trait, the dominant trait will show. The only way for a recessive trait to show is if the genotype contains both recessive genes.

The dominant traits for a betta are red, opaque, turquoise, steel, royal, butterfly, marble, Veil tail, and crowntail. The recessive traits are black, yellow, orange, Halfmoon, double tail, and plakat.

Using the main rule of genetics, breeding a crowntail with a plakat will most likely have more crowntails that plakats. Breeding a red betta with a black betta will have offspring mostly red.

Examples

  L l
l L l l l
l l L l l l
Long Fin (veiltail) x short fin (plakat)

Explanation: This table illustrates a cross between a long finned betta (such as a veiltail) and a short finned betta (such as a plakat). The long fin gene, represented by a capital L is dominant over the short finned gene, represented by the small l. This means that if a betta has a 1 gene for long fins and 1 gene for short fins, the betta will develop long fins. The only way for a betta to have short fins is to have both short fin genes, or l l. According to the table, a cross between a betta with long fins but a carrier of a short fin gene (L l) and a short finned betta (l l) will give a 50% chance of long fin with short fin gene (L l) and 50% chance of short finned bettas (l l).


  L L
l L l L l
l L l L l
Long Fin (veiltail) x short fin (plakat)

Explanation: This chart illustrates a cross between a pure long finned betta (L L) and a short finned betta (l l). This cross would give a 100% chance of a long finned betta, all carrying a short gene. This means that their genotype, or their genetic makeup, would look like L l. This also means that if one was to breed the offspring, there would be a 25% chance of a short finned betta, 50% chance of a long finned betta with a genotype of L l, and a 25% of a pure long fin.

Remember, these charts are not 100% accurate and should only be used to get an idea the offspring will look like if this betta and that betta breed. Now that you know about what traits are dominant and which ones are recessive, you can professionally breed bettas to have specific traits. Who knows, you may even discover a new tail type!