Taxonomy & naming
Trichogaster labiosa was described by Francis Day in 1877, from specimens collected in Burma (present-day Myanmar). It belongs to the genus Trichogaster, which houses the small-to-medium gouramis of South and Southeast Asia — including the dwarf gourami (T. lalius), the moonlight gourami (T. microlepis), and the three-spot gourami (T. trichopterus). The valid name as recorded in Eschmeyer's Catalog of Fishes is Trichogaster labiosa Day, 1877.
The species is placed in the family Osphronemidae, the true gouramis, all of which possess the suprabranchial labyrinth organ that allows them to breathe atmospheric air directly. Within the genus, T. labiosa sits among a cluster of Southeast Asian species characterised by bubble-nest construction and moderate body size. It has sometimes appeared in older literature under the genus Colisa, but current ichthyological consensus places it firmly in Trichogaster.
Morphology
Trichogaster labiosa reaches a maximum of around 3.5–4 in total length, males somewhat larger and more vividly coloured than females. The body is laterally compressed and oval in outline, typical of the genus. The species' defining feature is its unusually thick, fleshy lips — noticeably more developed than in T. lalius or T. trichopterus — which give it its common name and distinguish it on sight.
Adult males display a base body colour of orange to brownish-orange, overlaid with broken vertical blue-green bars or streaks along the flanks. The dorsal and anal fins tend to be pointed and may show orange and blue edging. Females are plainer, with a more subdued brownish-silver body and less defined barring. Both sexes carry the characteristic thread-like pelvic fins of the genus, which trail behind the fish and serve as chemosensory probes as well as display elements.
Habitat
Trichogaster labiosa is endemic to South Myanmar, where it inhabits slow-moving rivers, ponds, backwaters, and flooded areas with abundant surface and emergent vegetation. The habitat is typically shady and densely planted, with still or barely perceptible current — conditions that also characterise the environments of many other small Osphronemid species across Southeast Asia.
Water chemistry in the recorded range is moderately soft to slightly hard and slightly acidic to neutral: pH 6.0–7.5, hardness 4–15 degrees, and temperature 72–82 °F (72–82°F). As an obligate air-breather with a labyrinth organ, the species tolerates the low dissolved-oxygen levels common in warm, vegetated lowland waters — a biological reality that also shapes its aquarium care requirements.
Feeding
In the wild, Trichogaster labiosa is an opportunistic omnivore, feeding on small invertebrates, insect larvae, zooplankton, and algae picked from the water surface and vegetation. The pronounced lips are thought to assist in picking prey from crevices and plant surfaces.
In the aquarium it accepts a wide range of prepared and live foods. A varied diet of quality flake or small pellets supplemented with frozen or live foods such as Daphnia, brine shrimp, bloodworm, or Cyclops maintains good colour and condition. Small meals offered two or three times a day suit the species better than a single large feeding.
Mating
Trichogaster labiosa is a bubble-nest builder. Males construct a floating raft of mucus-bound air bubbles at the water surface, typically anchored among or beneath floating vegetation. The nest-building drive is triggered by warm temperatures and, in the aquarium, by calm, still conditions at the surface.
Courtship involves the male displaying to the female beneath the completed nest — flaring his fins, showing colour, and nudging her toward the surface. Males in breeding condition are more assertive than usual but are generally less aggressive toward females and other tankmates than the dwarf gourami. A male in full colour showing off a completed nest is one of the more handsome sights the family offers.
Breeding
Spawning takes place beneath the bubble nest in a characteristic gourami embrace: the male wraps his body around the female, eggs and milt are released simultaneously, and the male collects the fertilised eggs in his mouth and blows them into the nest above. A productive spawn may yield 500–1,000 eggs, though 500–600 is a more typical figure.
The male takes sole charge of nest maintenance and egg defence after spawning; the female should be removed to avoid harassment. Eggs hatch in 24–36 hours at 79–82 °F, and the fry become free-swimming after a further 2–3 days, at which point the male can be removed and feeding commenced. First foods should be very fine — infusoria, commercial liquid fry food, or vinegar eels — before graduating to newly hatched brine shrimp and powdered flake as the fry grow.
In the aquarium
Trichogaster labiosa is widely regarded as one of the better community gouramis: it is peaceful, hardy, undemanding about water chemistry within a reasonable range, and less aggressive toward conspecifics and tankmates than T. lalius or T. trichopterus. A tank of 20–25 US gal suits a pair or small group, with dense planting around the sides and back and some floating cover to encourage natural behaviour and dampen surface turbulence.
The labyrinth organ means the fish must reach the surface to breathe air; a tight-fitting cover glass keeps the layer of air above the water warm and humid, which is important for the health of the organ. Gentle filtration with minimal surface disturbance is ideal — a sponge filter or spray-bar outlet aimed along the surface rather than broken onto it suits the species well. Water temperature should be held in the 72–82 °F range; pH anywhere from mildly acidic to neutral is acceptable. Males can be kept together if the tank is large enough and sufficiently planted to break lines of sight, though a single pair or a male with two females is the more reliable approach. Its relative equanimity with tankmates makes it a good choice alongside small tetras, rasboras, peaceful barbs, and dwarf cichlids of comparable size.
Conservation
Trichogaster labiosa is assessed as Least Concern (LC) on the IUCN Red List, assessed 21 January 2010. The species is endemic to South Myanmar, where it remains reasonably widespread within its range. Although it is collected for the ornamental fish trade, export pressures have not pushed the population to threatened levels as of the most recent assessment.
Being restricted to a single country does make it inherently more vulnerable to large-scale habitat degradation — particularly the drainage of lowland wetlands, agricultural runoff affecting water quality, and deforestation of catchments — than a species with a broader range. Aquarium stock is widely available from captive-bred sources, and sourcing tank-raised individuals reduces any collecting pressure on wild populations.