The sparkling gourami (Trichopsis pumilus) is a small fish found throughout the lower Mekong River basin in Laos, Vietnam, Cambodia, Thailand, and in watersheds across central and southern (peninsular) Thailand. It is found in all types of still to slow-moving, predominantly lowland habitats, including swamp forest, peat swamps, floodplains, river tributaries, irrigation canals, paddy fields, and roadside ditches. The sparkling gourami displays a distinct preference for sluggish to still environments with dense growths of aquatic or riparian vegetation.
The sparkling gourami grows to an adult size of up to 1.5 inches long. It can be tricky to sex, but sexually mature males normally exhibit a more intense color pattern and develop longer ventral, anal, dorsal, and caudal fins than females. Sexually mature individuals can also be sexed by placing a strong light behind the fish, making the ovaries in females clearly visible below the swim bladder.
This species is also known as ‘pygmy gourami’ and ‘dwarf croaking gourami’. It is a popular aquarium fish, with the majority of fish in the aquarium trade produced on a commercial basis. It can be distinguished from congeners (similar species) by its small adult size and presence of a single solid dark midlateral stripe on the body, above which is a series of dark blotches forming a second stripe.
Trichopsis species are able to produce audible sounds via a specialized pectoral mechanism which is unique within the family Osphronemidae. The structure comprises modified pectoral-fin tendons and muscles which are stretched and plucked by the basal portion of the anterior fin rays in a similar way to guitar strings. The pectoral-fins beat alternately, each able to generate short or long bursts of sound. These sounds are produced by both sexes and they differ in temporal parameters, frequency, and pressure between the species. Studies suggest that Trichopsis species are able to settle conflicts without damaging each other physically by assessing factors such as body weight and length, which are transmitted by both visual and acoustic ‘croaking’ signals. During courtship the female produces ‘purring’ sounds in order to initiate spawning, and they are the only fishes in which this is known to occur.
The pygmy sparkling gourami prefers a temperature of 71°F to 82°F. They will do well with a pH of 5.0 to 7.5, and a hardness from 2 to 12°H or higher.
Pygmy sparkling gouramis should be maintained in an aquarium of 10 gallons or larger. It fares best in a well planted, shady aquarium with plenty of surface cover in the form of tall stem plants, floating plants, tropical lilies, or Cryptocoryne species. Driftwood (ZM2001) may also be used and other plants such as Microsorum or Taxiphyllum species may be attached to it. The addition of dried leaf litter (CS706) offers additional cover and brings with it the growth of microbe colonies as decomposition occurs. These can provide a valuable secondary food source for fry, while tannins and other chemicals released by the decaying leaves are considered beneficial. As it naturally inhabits sluggish environments strong, water movement should be avoided. An air-powered sponge (HYD112) filter set to turn over gently will provide adequate filtration. Keep a tight fitting lid on the aquarium and do not fill to the top since sparkling gouramis require occasional access to the layer of humid air that will form above the water surface, and is an excellent jumper.
The pygmy sparkling gourami is best maintained in a pair or small group, either alone or with very peaceful, similarly sized species. Much larger or more vigorous tank mates are likely to both intimidate and outcompete it. Small, schooling rasboras and tetras make good choices, as do diminutive loaches such as kuhli loaches and rosy loaches. They may eat small ornamental shrimp.
Pygmy sparkling gouramis will normally accept dried, live, and frozen foods. Good choices include frozen bloodworms(SF4792), live blackworms, and flakes (AL165). For maximum color, growth, and health these fish will look their best when given probiotics (AL169) in addition to a balanced diet.