DEAR PET TALK: How do Betta fish get their color?
— Nola’s Mom
DEAR NOLA’S MOM: These peppy little fish, also known as Siamese fighting fish are customarily kept as solo pets. The main colors include: blue, red, turquoise, yellow, white and orange — and there are numerous patterns, not to mention a variety of tail designs. According to scientist Young Mi Kwon, who with other researchers examined the species in 2021, Betta fish have been domesticated for more than 1,000 years.
“Siamese fighting fish, commonly known as betta, are among the world’s most popular and morphologically diverse pet fish, but the genetic processes leading to their domestication and phenotypic diversification are largely unknown.” Kwon did genome-sequencing on numerous individuals from the wild, and “domesticated ornamental betta. Given our estimate of the mutation rate from pedigrees, our analyses suggest that betta were domesticated at least 1,000 years ago, centuries earlier than previously thought.”
Kwon and their team also found that some wild populations show genetic evidence from ornamental Betta (those kept in tanks), which means Betta fish kept by humans were probably reintroduced into the wild at various points. “Furthermore, we find genes with signatures of recent, strong selection that have large effects on color in specific parts of the body, or the shape of individual fins.”
In short, the Betta fish you can buy for your home tank have received as much attention to breeding, as the dog who waits patiently for their bone. Other determinants on Betta fish colors can include light exposure. There is one type, called “marbled” which will change its color over time. However, if your little Betta fish is losing color, make sure you are cleaning the tank regularly, and have your tank at the correct temperature (75-80 degrees Fahrenheit) If it gets too cold, their immune system slows making them more susceptible to disease. Thanks for a fin-tabulous question — we have more to answer in forthcoming columns!
Sally Cragin is the director of Be PAWSitive: Therapy Pets and Community Education. Visit the organization on Facebook and text questions for Pet Talk to: 978-320-1335, or email sallycragin@gmail.com.
