About the Dwarf Gourami
Species Type: Freshwater Fish
Care Level: Easy. Does well in a slightly more narrow range of water parameters and shouldn't be used to cycle an aquarium. Will eat most prepared foods. May have some specific care requirements in terms of particular water parameters, social behaviors, food items etc.
Origin: Widely distributed in northern India, Pakistan and Bangladesh. Occurs in heavily-vegetated sluggish waters such as ponds, ditches, swamps and slow-flowing streams.
Compatibility/Temperament: Both shy and territorial, this fish can be maintained in a larger community aquarium with peaceful and quiet tankmates but usually not other gourami or active, boisterous fish. Males are territorial with other males. Sometimes other brightly-coloured fish will cause this fish to become aggressive. Should be maintained in sexed pairs only.
Certainly a beautiful fish, but one that must be carefully considered before being added to a community aquarium, both for the reasons above under Compatibility and on the basis of health. This species frequently carries a disease known as "dwarf gourami iridovirus" which some believe has been caused by successive generations of inbreeding of this fish in the far east. Imports of the species often have high losses, and this disease is now known to be transmittable to other species in the same aquarium with an infected gourami. Fish purchased should be very carefully examined, and if possible only acquired from local breeders.
Males can be distinguished by their larger size and brighter colouration. Females are usually tan or white with faint vertical blue/brown striping and blue markings on the anal fin and dorsal fin. Females also have rounded anal and dorsal fin tips, as well as a rounder body. This species is a bubblenest spawner, and moderately easy to spawn if the fish are both willing [the female may be injured if she is not ready], healthy and conditioned with good foods. The male cares for the nest and fry, and the female should be removed after spawning to avoid injury from the male. When the male makes the bubble nest he will bite pieces of plants up to add to the nest for more stability.
In common with all the species in the suborder Anabantoidei, this fish possesses an auxiliary breathing organ called the labyrinth, named because of the maze-like arrangement of passages that allow the fish to extract oxygen from air taken in at the surface. The fish must use this accessory method, and it allows the fish to live in oxygen-poor muddy waters. To accommodate this, the aquarium must be kept covered to maintain warm moist air above the surface.
The tank should be well-planted, and floating plants are important as the species, like all gourami, spends much time near the surface, browsing plant leaves and dangling roots for food. Floating plants also provide support for the bubblenest. Subdued lighting, partly achieved with floating plants, will calm the fish.
Several colour varieties exist, developed by breeders, including the blue morph, flame morph, neon red morph, and neon blue morph. Requirements and maintenance are the same as for the type species.
In 1882, F. Hamilton first described this species as Trichopodus lalius. It was transferred into the genus Colisa [erected by Cuvier in 1821] as Colisa lalia and remained there [apart from a 1999 reference by A.G.K. Menon to the species as Polyacanthus lalius] until 2009 when it was assigned to Trichogaster [see summary explanation below]. This genus name comes from the Greek thrix (hair) and gaster (belly), a reference to the thread-like pelvic fins that contain taste cells at the tips. The species name was also changed from lalia back to lalius [a noun] in accordance with the International Code of Zoological Nomenclature. Given that this is a very recent reclassification, the subject species will be frequently encountered as Colisa lalia.
Until 1923, Trichogaster was used as the genus for the small gourami species and Trichopodus for the larger species. When the genus Trichopodus was established by Lacepede in 1801, it was not usual to designate a type species (as it is now), and later ichthyologists frequently designated one. A "type species" is the species that exhibits all the scientific characteristics for that genus, normally today the first such species to be described, and all species assigned to that genus will also share those characteristics. Topfer & Schindler (2009) detail the matter of the type species designations and errors respecting Trichogaster and Trichopodus; the end result was that in 1923, Dr. George S. Meyers incorrectly assumed the type species earlier assigned for Trichogaster and consequently established Trichogaster as the true genus in place of Trichopodus (which name became a synonym for Trichogaster) for the larger gourami species. Colisa was then selected as the genus for the small (dwarf) species previously assigned to Trichogaster.
This state remained (although in the literature there was frequent confusion) until 1997 when E. Derijst pointed out the error of the assumed type species by Meyers [see Topfer 2008]. R. Britz (2004) obsoleted the name Colisa, but its popularity continued in the literature. In 2008, J. Topfer thoroughly investigated the issue and recommended renaming of the species and K.-H. Rossmann (2008) followed. In 2009, Topfer & Schindler established Trichopodus as a currently valid genus of Osphronemidae, which includes the four large gourami species, Trichopodus trichopterus, T. leerii, T. microlepis and T. cantoris. The Colisa species reverted back to the genus Trichogaster as Trichogaster chuna, T. fasciata, T. labiosa, T. lalius, and T. bejeus. The species names of this genus were also corrected grammatically in accordance with the rules of the ICZN [Schindler 2009]. The California Academy of Sciences--Ichthyology [W.N. Eschmeyer] has adopted the afore-mentioned revisions.
Britz, R. (2004), "Why Colisa has become Trichogaster and Trichogaster is now Trichopodus," AAGB Labyrinth 136, pp. 8-9.
Derijst, E. (1997), "Nota over de geldigheid van de genusnamen: Trichogaster Bloch & Schneider, 1801; Trichopodus Lacepede, 1801; Polyacanthus Cuvier, 1829 en Colisa Cuvier, 1831 (Perciformes: Belontiidae)...," Aquarium Wereld 60 (9), pp. 217-236.
Rossmann, K.-H. (2008), "Neue Namen fur die Fadenfische?" Der Makropode [Zeitschrift der Internationale Gemeinschaft fur Labyrinthefische] 30(3), pp. 79-80.
Schindler, I. (2009), "On the spelling of the Species name of the genus Trichogaster (formerly Colisa) and Trichopodus," Der Makropode 1/09.
Topfer, J. (2008), "Lacepede-2. Teil: Seine Labyrinthfischgattungen Osphronemus, Trichopodus und Macropodus sowie die Gultigkeit der Namen," Der Maropode 30(2), pp. 41-52.
Topfer, J. & Schindler, I. (2009), "On the type species of Trichopodus (Teleostei: Perciformes: Osphronemidae)," Vertebrate Zoology 59(1), pp. 49-51.
Dwarf Gourami Diet
Omnivorous by nature (feeding on insects, small invertebrates, aufwuchs [algae growing on rocks, etc]), it accepts most prepared foods. Supplemental feedings with frozen daphnia and bloodworms, or live foods like artemia (brine shrimp), worms and insects will bring out the best colouration. Fruit flies are also a good snack, and they can easily be raised in a small jar.
Males attain 3 inches [some sources say slightly larger], females are smaller at 2.5 inches.
Minimum Tank Suggestion
24 inches in length for a pair.
Ideal water parameters for Dwarf Gourami
Soft to moderately hard (hardness < 18 dGH), acidic to slightly basic (pH 6 to 7.5) water, temperature 23-28C/73-82F. Available fish will normally be commercially raised and suited to the ranges given for hardness and pH, but wild-caught fish must be kept in soft, acidic water.