[Ebook] 500 freshwater aquarium fish - Gouramis and Relatives

Gouramis, along with some of their close relatives, such as the Siamese Fighting Fish (Betta splendens) and the Combtail (Belontia signata), have been strong favorites within the hobby for the best part of 100 years. For example, the Dwarf Gourami (Colisa Mia) was first imported into Europe in 1903, while the Paradise Fish (Macropodus opercularis) has been known even longer, being the first “tropical” fish to be imported into Europe way back in 1869.

These fish, along with the Pikehead (Luciocephalus pulcher – family Luciocephalidae), make up the suborder Anabantoidei, commonly referred to as the labyrinthfishes. Closely related to them is the suborder Channoidei, with its single family, the Channidae (the snakeheads).

Other fish, such as the Badis (Badis badis) and its relatives, the leaf fishes (Monocirrhus, Polycentrus, and other species) constitute the family Nandidae (suborder Percoidei). The nandids are deemed by some authorities to have some affinity with the Anabantoidei.

Anabantoids possess an auxiliary respiratory organ known as the labyrinth. This allows them to take in air at the water surface and thus survive in conditions in which the oxygen concentration fluctuates from time to time (and may even fall to dangerously low levels). The labyrinth is located in a special chamber just above and behind the gills, and consists of folds of tissue served by a rich blood supply. Air is gulped in at the water surface and passed into the labyrinth chamber, where the oxygen is extracted, enabling labyrinth-bearing fish to survive in oxygen-deficient waters that would be unbearable for many other fish. Most species of anabantoids have become so dependent on the labyrinth that they will actually drown if prevented from surfacing for air.

The labyrinth is also used by many anabantoids to construct bubble nests, either at the water surface or under a broad submerged leaf or other appropriate surface. In these species, spawning occurs under the nest. The eggs are deposited among the bubbles by one or both parents, one of whom (the male) subsequently mounts guard until the eggs hatch and the resulting fry become free swimming. Other species dispense with nests altogether. Alternatively, they may incubate their eggs orally until they hatch. Both types of anabantoids (nestbuilding and mouthbrooding) will be featured in this section.

Among them will be all the well-known species referred to as “gouramis.” Although many of the best-known anabantoids are known as gouramis, the term itself cannot be precisely defined. It is simply one that over the years has been applied to some species in a genus but not others, to some genera but not others, and to some families of anabantoids but not others. If there is a “true” gourami at all, it is the Giant Gourami (Osphronemus goramy) . Fish carrying the gourami name tag occur in various genera, families, and subfamilies.

[Ebook] 500 freshwater aquarium fish – Gouramis and Relatives

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