The giant gourami, also known as the common gourami or true gourami, is a large food fish native to Southeast Asia. Giant gouramis are also sometimes kept as pets. These fish are omnivores, which means they feed on water weeds, smaller fish, and crustaceans in the wild. Adult fish typically have a blunt head and an ovular body, and are dark brown in color. Males of the species can sometimes display aggression towards one another, and vary slightly in appearance from the females.
Known scientifically as Osphronemus goramy, giant gouramis are often striped when young. Immature fish may be orange or reddish-brown in color, with brown stripes. Adult fish typically lose these stripes and become dark brown, though some giant gouramis have been known to turn pink or white as they mature. Scales may bear a silver iridescence.
These fish are known as giant gourami because they can grow to a length of 28 inches (71 cm). In the wild, they live in shallow pools. The giant gourami is a labyrinth fish, a type of freshwater fish possessing a special organ that allows it to breath air from the water's surface. This organ makes the giant gourami well-adapted to oxygen-depleted, weedy, and shallow waters. It also means that the giant gourami can survive out of the water for hours, making it easy to transport for breeding and pond-stocking purposes.
Males and females of this species generally vary in appearance. Males will usually display a "nuchal hump," which makes the forehead appear swollen. Males of the species also have more sharply pointed dorsal and anal fins than the females. These fish breed via bubble nest, constructed among the leaves of water plants at the water's surface. Fry emerge from the nest about two weeks after the eggs are laid.
While giant gouramis are often kept as pets, they are large, predatory fish and should be kept in a large aquarium with other large, non-aggressive fish. Some giant gourami hobbyists believe, however, that one can train a giant gourami not to eat its tank mates by never introducing it to live food in captivity.
Because these are large fish, they should ideally be kept in a large aquarium when in captivity. Appropriate tank size can vary according to the size of the fish being kept, but a 40-inch (101 cm) tank is considered the minimum size for a small giant gourami. These fish seem to thrive best at water temperatures between 68 and 86 degrees Fahrenheit (20 to 30 C). In captivity, they can be fed on blood worms, earthworms, small fish, fish pellets or flakes, or insects. Oatmeal, lettuce, and spinach can be fed to take the place of water weeds in the captive gourami's diet.