Betta splendensSiamese Fighting Fish

Geographic Range

The wild Siamese Fighting fish can be found swimming amongst the inland waters of the Orient. It is native to Thailand, but can be found worldwide in pet stores as a domesticated fish. (Hargrove 1999)


Betta splendens live in thickly overgrown ponds and in only very slowly flowing waters such as shallow rice paddies, stagnant pools, polluted streams, and other types of areas in which the water has a low-oxygen content. (Hargrove 1999)

  • Aquatic Biomes
  • lakes and ponds
  • rivers and streams

Physical Description

The Betta, on average, is 7.5 centimeters in length. Its body shape is streamlined, allowing it to slip smoothly and effortlessly through open water. The fish's body is covered with scales that overlap each other like the shingles on the roof of a house. These scales consist of thin, transparent plates that help protect the Betta's body from injury and add streamlining for efficient gliding. A mucus layer also covers the scales to provide the fish with extra smoothness and to protect against invading parasites and infection. The Betta's scales grow out from the skin and are generally lacking in color. The fish's true color actually comes from pigment cells (chromatophores) located in the skin itself.

In the wild, the fish uses its coloration to ward off predators and to attract mates. Wild Bettas do not possess the vibrant bright red, lime green, and royal blue colors of their selectively bred counterparts. In fact, they are unusually dull and drab. However, captive-bred Betta males have adopted these new colors and use them to their advantage in mating displays.

The actual colors of a Betta are layered. In order to produce a Betta of specific color, other colors that are layered on top must first be "stripped away" through selective breeding. The top color is blue; next is red, then black and finally yellow.

Bettas have mouths that are upturned, indicating that they are a top feeder and will scoop up their food on the water's surface. Their fins are used not only for propulsion through the water, but for maintaining balance and turning in different directions. They have one caudal fin, one dorsal fin, two pelvic fins, one anal fin, and two pectoral fins. (Hargrove 1999)


Mating begins with the male Betta building a nest of bubbles. To build this nest, the male swims to the surface, takes a gulp of air and spits out a mucus-coated air bubble. He then quickly takes another bubble of air and releases it near the first one. This process continues for hours with occasional breaks for food or to court the female. After awhile, the nest begins to take on a definate shape. However, the shape and size varies.

Once the nest is nearly complete, an extremely intense and often rough courtship begins. The male very aggressively pursues the female, attempting to entice her under the nest. In his efforts to bring her to the nest, he can be quite brutal if she doesn't willingly respond. More often than not, by the time the first spawning embrace begins, the female's fins are badly torn and she may even be missing some scales.

After spawning has occured, the male then guards the nest, taking care of the eggs until the young hatch 24 to 48 hours later, depending upon the temperature of the water. The young Bettas don't begin to show very much color or fin shape until they are about three months old. At about this time, males begin to fight with one another. It is also quite easy to sex Bettas around this age, as the males are usually more brightly colored and have longer fins than the females. The fish reaches sexual maturity around five months. (Ostrow 1989)


  • Average lifespan
    Status: captivity
    2 years


During the dry season, most Bettas are able to bury themselves in the bottom of their dried up habitat. There, they can live in moist cavities until water once again fills the depression during a rainy period. The fish can survive even if thick, clay mud is all that is left of the water. They do not survive total drying out of the bottom. (Vierke 1988)

A well-known behavioral characteristic of the Betta is fighting. Male Bettas, more commonly than females, instictively fight with one another to defend their territory. In the Orient, the fish's animosity towards its own kind is capitalized upon through the medium of staged fights. Fighting fish have been bred for competitive fighting for centuries. Considerable sums of money are exchanged in wagers on these fights, which are illegal in the United States. (Ostrow 1989) Wild fighting fish rarely keep up their fights for more than 15 minutes, unlike the cultivated varieties which are considered poor if they fight for less than an hour. (Rodgers 1990)

In reproduction, the Bettas have their own choreographed dance. When the female is finally ready to spawn, she approaches the male under the nest, swimming towards him in an oblique, head-down position with her fins closed against her body. This approach seems to signal the male that she is ready to mate, and he approachs her more gently than his previously aggressive displays. Before the first spawning embrace begins, there may be a few more mutal displays under the nest, during which time the colors of both fish become very intense. With fins spread and colors flashing, the pair begins to "dance". (Ostrow 1989) The fish circle one another, nudging each other in the sides with their snouts. The courtship ends with the male turning the female on her side and wrapping himself around her. He then tightens his grip, turns her upside down, and, in a short while, lets her go. As she remains suspended in the upside-down position, he stations himself beneath her. The female begins to lay 3-7 eggs at a time, to a total of several hundred eggs. As these slowly sink, the male catches the whitish eggs in his mouth. He then coats the eggs with mucus, swims up to his nest, and blows them into the mass of bubbles. While the male Betta is doing this, the female recovers from the embrace. This procedure is repeated until all the eggs are laid, with the male looping himself round the female each time to fertilize the eggs as she lays them. Finally, the male drives the female away. (Rodgers 1990)

Communication and Perception

Food Habits

Wild Betta splendens feed mainly on insects that have fallen into the water. Because of their rapid metabolic rate, Bettas need to eat frequent, small "snacks", such as algae, to hold them over until their next big meal. (Hargrove 1999) Five different feeding methods have been observed in the Betta: snapping, scooping/gulping, grazing, jumping, and spitting. Snapping is the method most commonly used to "capture" their morsels of food. (Vierke 1988)

Economic Importance for Humans: Positive

Bettas are kept as pets for the enjoyment of humans.

Conservation Status

The Betta is not endangered.


Dianna Sturgeon (author), Milford High School, George Campbell (editor), Milford High School.


bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.


uses smells or other chemicals to communicate


having the capacity to move from one place to another.


specialized for swimming

native range

the area in which the animal is naturally found, the region in which it is endemic.


found in the oriental region of the world. In other words, India and southeast Asia.

World Map


uses touch to communicate


Hargrove, M. 1999. The Betta: an Owner's Guide to a Happy Healthy Fish. New York: Howell Book House.

Ostrow, M. 1989. Bettas. New Jersey: T.F.H. Publications, Inc..

Rodgers, N. 1990. The Marshall Cavendish Wildlife Encyclopedia. New York: Marshall Cavendish Corp..

Vierke, J. 1988. Bettas, Gouramis, and Other Anabantoids. New Jersey: T.F.H. Publication, Inc..