Betta fish

Common Name:

Betta fish

Scientific Name:

Betta splendens

Type:

Fish

Diet:

Omnivore

Average Life Span In The Wild:

2 years

Average Life Span In Captivity:

2 to 5 years

Size:

2 to 3 inches long

What is a betta fish?

Betta fish—also known as Siamese fighting fish—are among the oldest species of domesticated fish. Their scientific name, Betta splendens, combines two languages: Malay for “enduring fish,” and the Latin word for “shining.” This species, with its many varieties, is the most common betta fish found in aquariums and pet stores, but it has more than 70 relatives, including the endangered Betta miniopinna and Betta Persephone.

Betta splendens are known for their stunning colors, decorative fins, and tendency to fight. These characteristics are much more pronounced in captive betta, which have been bred for those traits since the 14th century A.D. Early bettas were made to fight for human entertainment, like cockfighting, and were popular among Thai royalty. Today, betta fighting is illegal in many countries.

Although they are often considered to be easy pets, betta fish are sometimes mistreated by owners who aren’t aware of what they need to stay safe and healthy.

Habitat

Betta fish originated from Thailand but can be found in nearby countries such as Malaysia, Indonesia, Vietnam, Laos, and Cambodia. Wild bettas live in shallow, freshwater areas such as rice paddies, stagnant ponds, marshes, and slow-moving streams. Being used to Asian climates, they prefer warm water around 80º Fahrenheit. Colder water can cause them to become lethargic, stop eating, or become more prone to disease or infection. Their diet mainly consists of plankton, crustaceans, and larvae.

Because their usual habitats are extremely low in oxygen, bettas have evolved to breathe air at the water’s surface. This ability develops over time: hatchlings rely on their gills, but adults gulp air and capture the oxygen from it using something called a labyrinth organ, which is attached to the gills and functions similarly to a human lung.

Appearance

Captive bettas have been selectively bred for their intense rainbow colors—bright reds, greens, blues, oranges, pinks, and more, as well as intricate color combinations. Rare, coveted colors include turquoise, lavender, and albino. Males are brighter than females and become even more intensely colored when mating or fighting. Selective breeding has also changed the length and shape of their fins: of the many variations, delicate, ribbon-like fins and flowing tails are the most iconic.

Although the species is renowned for its stunning appearance, wild bettas are smaller with shorter fins, and are a dull gray, green, olive, or brown.

Fierce fighters

In the wild, betta fish are naturally territorial, and males instinctively fight one another. Before battle begins, they spread their fins and flare their gills to make themselves look bigger. The drawn-out fights can be brutal: the fish nip at each other’s fins, causing physical damage, until the loser admits defeat or is killed.

Mating and reproduction

Before mating, the male spends hours blowing bubbles at the water’s surface to build what’s called a mucus bubble nest. He then puts on a display to attract a female, becoming brighter and spreading out his fins. If a female approves of the nest, she turns darker to show her interest.

During mating, the male chases the female—sometimes nipping at her fins—before their nuptial embrace. Flipping the female upside down, he wraps his fins around her, and fertilizes eggs as she releases them. After a short rest, they repeat the process several times.

Like seahorses, male bettas care for their young. Once the female has laid her eggs, she typically leaves. (Some females attempt to eat their eggs, however, and the male may kill her if he thinks she poses a threat.) He then gathers the eggs in his mouth, spits them into the nest, and watches over them for the up to 48 hours it takes for the babies, called fry, to hatch. The father will also fight to defend the eggs from rival males. A few days after the fry have hatched, when they’re able to swim independently, the father leaves his brood.

Popular pets

Because of their beautiful colors and long, decorative fins, male bettas—like other ornamental fish—are popular pets. Often marketed as easy starter fish, they can cost as little as two dollars and are sometimes given out as party favors.

However, the misconception that betta fish are easy to raise can lead to mistreatment. People who keep betta fish as pets should be mindful of the potential for violent conflict by keeping two males together. Bettas also need plenty of space to remain healthy, and lots of plant life to keep them stimulated.

Owners should also watch out for infection and diseases such as fin rot, dropsy, and swim bladder disease. While Betta fish can tolerate dirty water for a short period, long exposure can cause velvet disease, a parasitic infection that makes the fish look like it’s covered in gold dust.

Threats to survival

Although bettas are plentiful in captivity, the species is listed as vulnerable by the International Union for the Conservation of Nature. In the wild, betta fish are threatened by pollution from urban wastewater, as well as agricultural and industrial chemical run off. Much of their habitat has also been destroyed by human activity, including the development of palm oil plantations.

Human medication can also have an impact. The popular anti-depressant Prozac, which reaches aquatic environments through the sewage system, has been shown to reduce the time bettas spend building nests and have harmful effects on nest size, spawning duration, and hatching rate. Fathers that have been exposed to Prozac are also more likely to eat their own eggs.

When released outside their native area, betta can also pose a threat to other species through predation, competition, and disease.