The Belontiidae family, commonly known as gouramies, is composed of approximately 12 genera and 46 species, and is the largest and most diverse family in the Anabantoidei suborder. Gouramies are restricted to fresh water and are capable of inhabiting stagnant, low-oxygen areas due to the existence of an air-breathing organ called the labyrinthine (in Physical Description below). In addition, the Belontiidae family contains some of the most popular fish in the aquaria trade. One species, Betta splendens (Siamese fighting fish), has been in cultivation for over 100 years and captive individuals scarcely resemble the wild variety (see Economic Importance for Humans). Due to their pugnacious behavior, many gouramies have been used in behavioral studies as well (see Behavior). (Berra, 2001; Nelson, 1994; Wheeler, 1985)
All members of the Belontiidae family inhabit freshwater and are indigenous to Africa and Southern Asia. They can be found in Pakistan, India, China, Korea to the Malay archipelago, Indonesia and Borneo. However, due to their popularity in the aquarium trade and ease of transport, belontiids are frequently shipped far beyond their natural range. Several species that now live in the Philippines and United States originally escaped from the aquarium trade (Lever 1996 from Berra 2001 pg. 480, 487). (Berra, 2001; Nelson, 1994)
Gouramies are uniquely adapted to the stagnant waters of tropical areas. They inhabit swift streams, the backwaters of large rivers, brackish lagoons, and potholes. They are most common in stagnant areas with dense aquatic or overhanging vegetation. With the ability to breathe air directly from the atmosphere, gouramies are able survive in marginal to anoxic waters. (Graham, 1997; Moyle and Cech, 2000; Nelson, 1994; Wheeler, 1985)
- Aquatic Biomes
- lakes and ponds
- rivers and streams
- temporary pools
Most gouramies are small (10 cm or less) and have elongate and cylindrical bodies. Others are deep-bodied and compressed. Gouramies have rounded tails and the anal fin base is much longer than the dorsal fin base in most species. In some gouramies, the first ray on the pelvic fin is elongated and is used as a tactile (touch-sensing) organ. After extensive breeding in captivity, the color and fin form have changed considerably in some gouramies. Sexual dimorphism has been reported for some members of this family. (Berra, 2001; Moyle and Cech, 2000)
One of two distinct physical features is the labyrinthine organ located above the gill chamber, which allows gouramies to breathe atmospheric air by capturing air bubbles from the surface water and holding them in the labyrinthine organ until they are expelled through the gill covers. “This unique organ is formed of highly vascularized, convoluted tissue, supported by an enlarged dorsal element of the gill arches” (Johnson, G.D. and A.C. Gill 1998). The bubbles taken in by gouramies are also important in hearing. Air bubbles are stored adjacent to membranous windows on either side of the cranium, which contains the inner ear. Slight vibrations picked up by the air bubble are easily transmitted to the inner ear through this membranous window. The second feature is a long body cavity that allows the swimbladder to extend into the caudal region. (Click here to see a fish diagram). (Johnson and Gill, 2002; Moyle and Cech, 2000)
- Sexual Dimorphism
- sexes colored or patterned differently
- sexes shaped differently
After spawning, female gouramies release their eggs into the water. The eggs are gathered by the male and left in a nest near the surface until fry hatch. (Moyle and Cech, 2000)
Female gouramies use pheromones to attract males during spawning. The female deposits eggs into the water and they are collected by the male to deposit into the nest. The courting behavior of some gouramies is quite elaborate and spawning territory is maintained aggressively by the male. (McKinnon and Liley, 1987; Moyle and Cech, 2000)
Gouramies use air bubbles in constructing their nests. They create a nest of froth by expelling mucous-covered bubbles at the surface, often beneath leaves. After gathering the eggs, the male deposits them into the froth nest. The nest has a dual purpose: to keep the developing young close together for protection and to keep them near the water’s surface where it is well oxygenated. (Helfman, et al., 1997; Moyle and Cech, 2000; Wheeler, 1985)
- Key Reproductive Features
- gonochoric/gonochoristic/dioecious (sexes separate)
Male gouramies guard the froth nest and maintain it by producing new bubbles as older ones break down. If juveniles try to leave the nest early, the male transports them back by carrying them in his mouth and spitting them back. In some genera (Macropodus and Betta) mouthbrooding has been reported as well. (Graham, 1997; Helfman, et al., 1997; Moyle and Cech, 2000)
- Parental Investment
- male parental care
No specific information was found concerning lifespan or longevity for this family.
Members of the Betta (fighting gouramies) genus have been used extensively in behavioral studies. Male fighting gouramies are extremely belligerent toward each other and they are often bred to fight, as with the fighting cocks. Talking gouramies use the air-breathing organ (labyrinthine) to produce a croaking sound, which is used in establishing territories and dominance hierarchies. Additionally, some gouramies use an elongated pelvic fin ray in exploratory behavior. The ray is directed forward to gather information about the fish’s surroundings or sense another individual as it approaches. Another interesting behavior of gouramies is the socially controlled synchronous air breathing. Groups of individuals in both Trichogaster and Colisa come to the surface and gulp air simultaneously in a temporary school to lessen the chance of predation while surfacing. (Berra, 2001; Graham, 1997; Helfman, et al., 1997)
Communication and Perception
Gouramies use several forms of communication: Talking gouramies use croaking to communicate, a modified pelvic fin ray is used as a tactile organ, and chemical signals are used during mating. The former two are described in more detail in the Behavior section and the latter is discussed in Reproduction. (Graham, 1997; McKinnon and Liley, 1987)
Members of the genera Belontia, Trichopsis, and Macropodus are omnivores, while Trichogaster is primarily herbivorous, and Betta and Colisa are carnivorous, feeding on shrimp, fish and insects in or out of water. Colisa uses the same technique as archerfishes to prey on insects just above the water. Bullets of water are created by compressing the gill covers and forming a groove using the tongue and palate. The fish “shoots” insects out of overhanging vegetation with these bullets and eats them when they hit the water. (Graham, 1997; Helfman, et al., 1997)
One impact of predation on gouramies is the frequency and location of atmospheric air breathing. In the presence of predatory birds or fish, some gouramies hide in mats of aquatic vegetation and surface less frequently. Other gouramies form temporary schools when they come up in order to deter predators. This “synchronous air breathing” is discussed above in Behavior. (Graham, 1997)
Because gouramies are uniquely adapted to harsh conditions, such as hypoxia (water without oxygen) and desiccation, they are an important predator in the stagnant and intermittent waters of Asia. In addition, air breathing serves to protect gouramies from excessive water pollution so they play an important role in the biological control of insects in urban areas. This is discussed further in Economic Importance for Humans. (Graham, 1997; Wheeler, 1985)
Economic Importance for Humans: Positive
Many gouramies are popular aquarium fishes because of their bright coloration, small size, and interesting reproductive behaviors. Members of the genus Betta, fighting fishes, have been used extensively in genetic and behavioral studies. Fighting fishes are also bred for entertainment and gambling in some countries. Finally, members of the genus Trichogaster have been cultured in ponds as food fish. (Berra, 2001; Helfman, et al., 1997; Johnson and Gill, 2002)
Experiments with Pseudosphromenus cupanus show that breathing air at the surface instead of consuming oxygen entirely from water lessens the absorption of toxic pollutants, which makes gouramies more effective in the biological control of insects. For example, mosquito larvae form the main diet of fish in the Betta genus. Each adult consumes approximately 10,000 to 15,000 mosquito larvae each year, significantly reducing the mosquito populations and mosquito-related illnesses. (Graham, 1997; Wheeler, 1985)
Economic Importance for Humans: Negative
No specific information was found concerning any negative impacts to humans.
There are 11 species of concern within the genus Betta. Of these, three are listed as critically endangered, one is listed as endangered, and seven are listed as vulnerable. Additionally, Parosphromenus harveyi is listed as endangered, and Belontia signata and Malpulutta kretseri are listed as low risk depending on conservation efforts. (The World Conservation Union, 2002)
- IUCN Red List [Link]
- Not Evaluated
R. Jamil Jonna (author), Animal Diversity Web.
living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.
living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.
uses sound to communicate
living in landscapes dominated by human agriculture.
- 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.
an animal that mainly eats meat
uses smells or other chemicals to communicate
to jointly display, usually with sounds, at the same time as two or more other individuals of the same or different species
- dominance hierarchies
ranking system or pecking order among members of a long-term social group, where dominance status affects access to resources or mates
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
- external fertilization
fertilization takes place outside the female's body
union of egg and spermatozoan
A substance that provides both nutrients and energy to a living thing.
mainly lives in water that is not salty.
An animal that eats mainly plants or parts of plants.
An animal that eats mainly insects or spiders.
referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
- male parental care
parental care is carried out by males
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.
an animal that mainly eats all kinds of things, including plants and animals
found in the oriental region of the world. In other words, India and southeast Asia.
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
- pet trade
the business of buying and selling animals for people to keep in their homes as pets.
chemicals released into air or water that are detected by and responded to by other animals of the same species
an animal that mainly eats fish
Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).
associates with others of its species; forms social groups.
living in residential areas on the outskirts of large cities or towns.
uses touch to communicate
defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
living in cities and large towns, landscapes dominated by human structures and activity.
uses sight to communicate
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Graham, J. 1997. Air-breathing fishes: evolution, diversity, and adaptation. San Diego, CA: Academic Press.
Helfman, G., B. Collete, D. Facey. 1997. The Diversity of Fishes. Malden, MA: Blackwell.
Johnson, G., A. Gill. 2002. Perches and Their Allies. Pp. 193 in W Eschmeyer, J Paxton, eds. Encyclopedia of Fishes – second edition. San Diego, CA: Academic Press.
McKinnon, J., N. Liley. 1987. Asymmetric species specificity in responses to female sexual pheromone by males of two species of Trichogaster (Pisces: Belontiidae). Can. Journal Zool. Dep. Zool., Univ. British Columbia, Vancouver, B.C., 65 no. 5: 1129-1134.
Moyle, P., J. Cech. 2000. Fishes: An Introduction to Ichthyology – fourth edition. Upper Saddle River, NJ: Prentice-Hall.
Nelson, J. 1994. Fishes of the World – third edition. New York, NY: John Wiley and Sons.
The World Conservation Union, 2002. "IUCN 2002" (On-line). 2002 IUCN Red List of Threatened Species. Accessed July 08, 2003 at http://www.iucnredlist.org/.
Wheeler, A. 1985. The World Encyclopedia of Fishes. London: Macdonald.