Taxonomy & naming
Trichogaster bejeus was described by Francis Hamilton in 1822 as Trichopodus bejeus, from the Brahmaputra River at Goalpara in Assam, in his foundational Account of the Fishes Found in the River Ganges; no type specimens survive, but Hamilton's original unpublished illustration was reproduced by Britz (2019). For most of the twentieth century the name sat unused: the banded gourami was universally called Colisa fasciata and later Trichogaster fasciata, under Bloch & Schneider's older (1801) name. Knight, Nallathambi, Vijayakrishnan & Jayasimhan (2022), re-examining the original descriptions and topotypic material, showed that fasciata properly applies to the fish the hobby calls the dwarf gourami — and resurrected Hamilton's bejeus as the valid name for the banded gourami. Eschmeyer's Catalog of Fishes has adopted that arrangement: Trichogaster bejeus (Hamilton, 1822) is valid, with Colisa ponticeriana Valenciennes, 1831 among its synonyms and the old combination Colisa fasciata still ubiquitous in earlier literature.
The genus Trichogaster — the small South Asian gouramis once grouped under Colisa — belongs to the family Osphronemidae and further contains the dwarf gourami (T. fasciata in the current sense), the honey gourami (T. chuna), and the thick-lipped gourami (T. labiosa). T. bejeus is the largest of the four and the one with the broadest natural range. Readers consulting older sources should simply map 'Colisa fasciata' and pre-2022 'Trichogaster fasciata' onto this species.
Morphology
The banded gourami is a moderately elongate, strongly laterally compressed fish, reaching up to 5 in total length, which makes it noticeably larger than the familiar dwarf and thick-lipped gouramis. The body profile is convex along the back and nearly straight along the belly; the caudal fin is slightly rounded. Like all Trichogaster, the pelvic fins are greatly reduced to single, elongated tactile filaments that the fish extends forward to probe its environment — a defining character of the group.
The coloration of adult males is attractive without being flamboyant. The base body colour ranges from olive-green to brownish-green, overlaid with a series of roughly oblique bars or bands in alternating blue-purple and orange that tilt diagonally backward from the dorsal surface toward the belly. The unpaired fins carry alternating dark and pale spots, and the lower edge of the anal fin typically shows a reddish-orange margin. Females are less colourful, with the barred pattern reduced or absent and the body more uniformly olive to yellowish. Juveniles of both sexes resemble females. Sexual dimorphism is further evident in fin shape at maturity: males develop extensions to the dorsal and anal fins that come to a point, while those of females remain rounded.
Habitat
Trichogaster bejeus is a fish of the lowland floodplain zone across its broad South Asian range, occupying a wide range of still and sluggish freshwater habitats: large rivers and their backwaters and oxbows, estuaries, ditches, ponds, swamps, flooded rice paddies, and heavily vegetated margins. It is strongly associated with dense aquatic and emergent vegetation — waterhyacinth mats, reed beds, pond weed — which provides both cover and a spawning substrate for the floating bubble nest.
As an obligate air-breather, the banded gourami is tolerant of habitats with low dissolved oxygen, and it thrives in the warm, still, oxygen-depleted water typical of tropical ponds and rice cultivation areas. Water conditions across its range vary considerably, but the species is generally found in soft to moderately hard, neutral to slightly acidic or slightly alkaline fresh water, with temperatures in the 72–82 °F range. It also tolerates brackish conditions near estuaries, which partially explains its wide distribution. The species is reported as benthopelagic but spends considerable time near the surface, where it gulps air and where males construct their bubble nests.
Feeding
The banded gourami is an opportunistic omnivore, accepting a wide variety of food items in the wild and in captivity. Natural prey includes small invertebrates — insect larvae, worms, small crustaceans — as well as algae and plant matter grazed from submerged surfaces and vegetation. The long pelvic filaments serve as touch organs and likely help the fish locate invertebrates among vegetation.
In the aquarium the species is unfussy and accepts most standard aquarium foods: quality flake and pellet diets, as well as live and frozen foods including bloodworm, Daphnia, brine shrimp, and Tubifex. Providing a varied diet that includes live or frozen invertebrate foods enhances colour and supports breeding condition, particularly in males. The species is not known to be aggressive at the feeding station except during spawning activity.
Mating
The banded gourami is a bubble-nest builder. Males construct a raft of mucus-bound air bubbles at the water surface, typically anchoring the nest to floating vegetation, leaf litter, or the underside of a broad leaf. Nest construction precedes spawning and the male's investment in it is substantial — he will maintain and repair the nest over the course of the spawning period.
Courting males become highly territorial and will display aggressively to rival males, erecting their fins and intensifying their colour. Courtship of the female involves persistent following and lateral displays. Males may become aggressive toward females outside of spawning, so some authors recommend keeping the species as pairs in tanks with adequate break-up cover rather than in groups. Spawning is most likely to be triggered in the aquarium by a slight rise in temperature, reduced water depth, a humid air layer above the surface, and the presence of floating plants.
Breeding
Once a female accepts the male, spawning occurs beneath the bubble nest. The pair engage in the typical embrace of labyrinth-fish breeding: the male wraps himself around the female, and eggs and milt are released simultaneously. The fertilised eggs, which are lighter than water, float upward into the nest; the male retrieves any that sink and returns them to the bubble raft. A single spawning session may produce 500–1,000 eggs, and the clutch can be deposited across several embraces.
After spawning the female should be removed, as the male may harass her. The male then guards the nest attentively, repairing broken bubbles and retrieving fallen eggs. At 79–82 °F, eggs hatch within 24–36 hours; the larvae are tiny and initially inactive, hanging in the nest. The male continues to tend them, and by approximately 3 days post-hatching the fry are free-swimming. At this point the male should also be removed. First foods for the fry are very fine: infusoria, rotifers, or commercial liquid fry food. Crucially, the air layer immediately above the water surface must be warm and humid — the fry's labyrinth organ develops over the first few weeks, and cold dry air during this period can be fatal.
In the aquarium
Despite its attractive coloration and relative robustness, the banded gourami is less commonly seen in the aquarium hobby than its smaller congeners the dwarf and thick-lipped gouramis — and the 2022 name change means it now often hides in shop lists and older books under 'Colisa fasciata'. Where available, it is an undemanding fish for an intermediate aquarist. It requires a tank large enough to accommodate its size — a single pair or small group warrants at least 25 US gal — with plenty of floating or surface-reaching plants to provide cover and spawning sites.
The species is generally peaceful in a community setting, though males will fight with one another in confined quarters, and spawning males can harass females and smaller tankmates. It is best kept as a pair or one male with two or more females, or in a single-species setup for breeding. Filtration should be gentle — strong currents will disrupt bubble nests and stress the fish — and the tank must have a tight-fitting, slightly raised lid to maintain a warm, humid air layer for the labyrinth organ. Water conditions are adaptable: the species tolerates a temperature range of 72–82 °F and pH from 6.0 to 7.5, making it suitable for most tropical freshwater set-ups without special chemistry adjustments. The banded gourami is also eaten as a food fish across parts of its native range, particularly in Bangladesh and Myanmar, which accounts for some of its common-name recognition beyond the hobby.
Conservation
The banded gourami is assessed as Least Concern (LC) on the IUCN Red List, reflecting its wide distribution across a large part of South and Southeast Asia and its tolerance of a broad range of lowland freshwater habitats including degraded environments such as rice paddies and urban ponds. The assessment, published in January 2010, was made under the name Trichogaster fasciata — the usage then current for this species, before the 2022 revision moved that name to the dwarf gourami — and noted medium resilience (minimum population doubling time of 1.4–4.4 years), low fishing vulnerability, and no evidence of population decline sufficient to warrant a threatened category.
The species is harvested as a food fish in parts of its range, and ornamental collection occurs at a low level, but neither appears to threaten the overall population. Habitat loss from drainage of wetlands, agricultural intensification, and water pollution is a broader concern for freshwater fish across the Indo-Gangetic Plain and Myanmar, and while the banded gourami's generalist habits buffer it against moderate habitat change, sustained degradation of floodplain wetlands could exert pressure over longer timescales. The species is not listed on CITES appendices and is not evaluated under the Convention on Migratory Species.