Fish
Gourami
Osphronemidae · also called gouramis, gourami fish
A gourami is a fish that breathes air. It comes from the warm, weedy, oxygen-poor swamps and ditches of Southeast Asia, and it survives there by gulping mouthfuls of air at the surface through a lung-like organ behind its head. It feels its way through murky water with a pair of long thread-like feelers, and in most species the male builds a raft of bubbles and guards the eggs alone.
Overview
Gouramis are the family Osphronemidae, freshwater labyrinth fish of South and Southeast Asia. The labyrinth organ — a folded, blood-rich chamber above the gills — lets them take oxygen from air, so they thrive in warm, stagnant water that would suffocate other fish. Many are so committed to air-breathing that they will drown if they cannot reach the surface.
Feelers and bubble nests
Most gouramis have their pelvic fins drawn out into long feelers that they sweep around to touch and taste their surroundings. To breed, the male builds a floating bubble nest, entices a female underneath, fertilises the eggs as they fall, tucks them into the nest, and guards them alone.
Kissers, bettas, and food fish
The kissing gourami’s “kiss” is actually a shoving match between rivals. The betta, or Siamese fighting fish, is a small, unusually aggressive gourami. And the giant gourami, up to 70 cm, is a major farmed food fish across the region.
Status
Least Concern for the widespread aquarium and food species, many farmed by the million. But peat-swamp specialists like the chocolate and licorice gouramis are threatened as blackwater swamp forest is drained and cleared for oil palm.
Gourami: common questions
Why do gouramis come to the surface to breathe?
Gouramis have a special organ, the labyrinth, a maze of thin, folded, blood-rich plates in a chamber behind the head, which works like a simple lung. The fish takes a gulp of air at the surface and absorbs oxygen from it through the labyrinth. This lets gouramis survive in warm, still, oxygen-poor water where other fish would suffocate, but it also means they are partly dependent on air, and an adult gourami prevented from reaching the surface, for example by a tank lid clamped tight over the water or a layer of surface scum, can actually drown.
Do kissing gouramis really kiss?
No, the kiss is a fight. When two kissing gouramis press their large, protruding lips together and push, they are engaged in a trial of strength, usually between two males or between fish contesting a feeding spot or territory, and the one that pushes the other back wins. Their thick lips are lined with fine teeth used for rasping algae, and the mouth-to-mouth shoving lets rivals test each other without the risk of biting injuries. It looks tender, but it is a low-stakes duel.
Are gouramis good community fish?
Many are, with some care. Small and medium gouramis such as the honey, pearl, and dwarf gouramis are generally peaceful and suit a calm community tank with gentle water flow, floating plants, and a warm, stable temperature, and they appreciate being able to build a bubble nest. The cautions are that males of the same species, and sometimes different species, can be territorial and quarrelsome, that the long pelvic feelers are tempting targets for fin-nippers like some barbs, and that the popular dwarf gourami is prone to a specific viral disease from poor farmed stock. A single male, or one male with a couple of females, usually works best.
What is the difference between a gourami and a betta?
A betta, the Siamese fighting fish, is a gourami, a small member of the same family, Osphronemidae. It shares the key gourami traits of air-breathing through a labyrinth organ and, in the male, building and guarding a bubble nest. The main differences are size and temperament, since bettas are small and, in the males, extremely aggressive toward other male bettas, to the point that they cannot be kept together, whereas most other gouramis are larger and, while sometimes territorial, are not usually kept as solitary fish. The flowing fins of pet bettas are a product of selective breeding.