Betta Fish: The Dazzling Siamese Fighting Fish

 Betta fish, also called Siamese fighting fish, are small, colorful fish that are native to Southeast Asia and common in the pet trade.

In Thailand, people call betta fish " pla kat ," which means "fighting fish," and it couldn't be a more appropriate name. Male bettas are known fighters, aggressively flaring their gills and nipping at the fins of other males or even females that get too close. In the wild, fights can last only 15 minutes, but people in Thailand have bred bettas that are capable of fighting for hours.

Bettas do well in captivity, and their aggression, which many find amusing, along with their vibrant colors have helped make the species popular as pets around the world. However, in their native home, the fish are slowly disappearing.

Where do betta fish come from?

A total of 73 types of betta live in the freshwater environments of Southeast Asia, and all of these varieties belong to the Osphronemidae family. But the species most people are familiar with is Betta splendens . These bettas originate from the Mekong and Chao Phraya river basins in Thailand formerly called Siam. The fish hang out in shallow, almost stagnant water such as swamps, floodplains, and rice paddies. In nature, animals chew on unlucky insects that fall into the water, as well as small larval mosquito crustaceans and other aquatic arthropods.

Bettas are generally small, 2.4 to 3.1 inches long 6 to 8 centimeters, and live about two years on average. In the wild, male bettas never grow the beautiful, flowing fins commonly seen on pet store bettas, with their wildly different shapes and vibrant golds, reds, blues, greens, and purples. Those features are the result of selective breeding, according to the University of Michigan Animal Diversity Web . Wild Siamese fighting fish have a dull green coloration and short fins, which flash to attract mates and ward off predators such as salamanders, cats and larger fish. The more extravagant captive males, however, seem to use their enhanced colors to their advantage, both to attract mates and to fight when defending territory.

Scientists have been particularly interested in bettas' bellicose behavior and the physiological mechanisms behind it. The fish have become a model organism for studying the behavioral effects of raw or il spilled fish, antidepressants such as Prozac and fluoxetine , dissolved drug therapies such as flutamide in waterways, and even depressants such as alcohol .

Fish aggression has also long been exploited for financial gain by people who play in fish fights. People in Southeast Asia have caught and bred Siamese fighting fish for centuries to compete in staged battles, which people bet on, similar to cockfights. Such organized fish fights are illegal in the United States . Even using a mirror to make fish think someone else is there is considered unethical, although some companies have produced branded "exercise mirrors" for betta fish to keep flexing their fins to compensate for boredom and depression .

How do betta fish reproduce?

Breeding behavior among Siamese fighting fish is a mixture of beauty and terror, as their courtship can get a bit dangerous. It starts with a male blowing bubbles. He swallows some air at the surface and then blows mucus-covered bubbles that settle on the surface of the water. The male does this for hours until a thick bubble nest forms. Then he chases after a female.

Male betta fish try to courteously entice a female under the nest at first by flashing their fins and flaring their gills. But if she doesn't respond or cooperate, the male can become violent, biting her tail and fins so they rip and tear off her scales, according to Animal Diversity Web.

Related: Weird Love: 11 Animals With Truly Weird Courtship Rituals

When the female is finally coaxed into mating, ready to accept the male, the two dance, spin around, and push each other sideways. The male eventually wraps a flipper around the female in an embrace, turns her upside down, and fertilizes her eggs. After releasing them, the female remains suspended on her back, as if in a trance, and releases a few fertilized eggs, usually three to seven at a time. The male catches the eggs in his mouth as they sink and covers them with mucus before sticking them to his bubble nest.

The male and female will perform this dance dozens of times until she has produced hundreds of eggs. When he's done, the male aggressively drives the female away and guards the bubble nest until the eggs hatch, 24 to 48 hours later, according to Seriously Fish . The male will protect the young for another three or four days while they finish absorbing the yolks. However, once the fry are free swimming, they are on their own. The young reach sexual maturity approximately five months later.

Are betta fish threatened?

Siamese fighting fish are considered vulnerable as their habitat has been lost to urban development and agricultural land, according to the International Union for Conservation of Nature IUCN Red List . Pollution from agriculture and cities has also threatened fish, and their population in the wild is declining. The IUCN has suggested that captive breeding programs can help save the wild population.

However, a large population of betta fish swim in aquariums around the world. The fish became a favorite of the pet trade and have only increased in popularity due to their easy care and striking colors not to mention cheap price; They are sold for as low as $2.49. The pet trade population of bettas is sourced almost entirely from captive populations, not the wild, according to Earth.com .

Bettas are easy to care for in part because they live in warm waters, typically 75 to 80 degrees Fahrenheit 24 to 27 degrees Celsius, and are perfectly fine living with no other fish around. Bettas can also breathe oxygen from both air and water due to a lung-like organ called the labyrinth.

In the wild, the labyrinth organ allows them to survive in poorly oxygenated water and when the water almost dries up. But in captivity, it means they can live in much smaller tanks than other fish and tanks that don't require constant oxygenation. Veterinarians, however, suggest that people keep the fish in a tank that is at least 2 gallons 7.6 liters, according to Adelphi University .