Gouramis are Perciformes that belong to the suborder Anabantoidei.
They are freshwater fish, and are native to Africa, Asia, the Malay Archipelago and the Philippines.
Gouramis are often very colorful. They are popular aquarium fish.
They are usually omnivorous. They eat algae and small invertebrates, such as insects.
Gouramis are sometimes known as labyrinth fish because they breathe air by using a labyrinth organ, which is located above the gills.
A labyrinth organ is made up of bony plates called lamellae, which are arranged in a maze-like structure and covered with many folds of skin tissue. These folds of tissue are lined with a large number of small blood vessels. Oxygen passes from the air to the fish's bloodstream via the labyrinth organ.
A gourami will use its gills to breathe water, but it will also breathe air by gulping air above the surface of the water.
Because gouramis can breathe air, they can survive in water with low oxygen levels.
They can even survive outside water for short periods, as long as they are kept moist.
Gouramis are not born with labyrinth organs. Fry (young fish) can only breathe through gills for the first few weeks of their lives.
Gouramis practice external fertilization and are oviparous (lay eggs).
Many male gouramis build "bubble nests".
A bubble nest consists of pieces of plants that are held together by bubbles that the male blows and mucus that the male secretes from his mouth.
By building a bubble nest, the male ensures that the fry stay near the surface of the water, where oxygen levels in the water are the highest. Because the fry do not have labyrinth organs, there must be enough oxygen dissolved in the water to meet all of their metabolic needs.
Paradise fish (Macropodus operculari), also known as paradise gouramis, are a species of gourami that are native East Asia, where they live in muddy waters with low levels of oxygen - in rice paddies, for example.
They were one of the first fish to be kept in home aquariums.
Male paradise fish build bubble nests.
The males use their bubble nests to attract females.
A female will watch a male build a bubble nest that is about half an inch thick and a few inches in diameter.
If the female appreciates his efforts, she will mate with him.
During mating, the male will embrace the female. The male will release sperm and the female will release eggs into the water.
After mating is finished, the male will gather the eggs in his mouth and then spit them out into the nest.
He will watch over the nest until the fry have grown large enough to fend for themselves.