About the Croaking Gourami
Species Type: Freshwater Fish
Care Level: Moderate. May tolerate only a narrow range of water parameters, have specific dietary requirements including frozen or even live foods, may have behaviors that severely limit potential tankmates or may require a specialized aquarium setup.
Origin: Thailand, Cambodia, Laos, Vietnam and the Indonesian islands of Borneo, Sumatra and Java. Occurs in shallow and sluggish or standing waters with thick vegetation.
Compatibility/Temperament: Peaceful, best kept in a small group of six. Well suited to community aquaria of similar non-aggressive fishes such as rasbora, loaches, characins, and catfish, provided these are not too active.
Typical of fish that occur over such a wide geographical area, this species can be varied in colouration and pattern; some authorities believe these variations may be distinct but closely-related species. The dorsal, anal and caudal fins of males usually have extensions and exhibit a sparkling metallic sheen in red or blue in various patterns. Females are much less vividly coloured.
When kept in a group, the males will regularly "battle" but not with fights; instead they display in pairs, flexing their bodies to create waves in the water that presumably are detected by the other fish as a sign of strength. During these displays as well as during courtship, the males make grating or croaking sounds like a rapid series of clicks. In a 1992 study, Friedrich Ladich et.al. determined that this sound is important not only in breeding displays but also in antagonistic displays of males to establish dominance. The "croak" is a series of double pulses generated by rapid beating of the pectoral fins. Another study by Ladich in 1998 established that the sounds vary according to the individual fish and the sound frequency had a role in determining the outcome of the encounter between rival fish.
Spawning is in typical anabantid fashion and the species is a bubblenest breeder. Following the male's embrace, the eggs are released by the female in little packets of 4-6 eggs each, and these packets are grabbed up by the male and spit into the nest. Anywhere from 150-200 eggs may be laid, and the male guards both the nest and the fry when they first hatch, spitting back into the nest any that fall out. Eventually he loses interest and at that point either the fry or the parents should be removed (if a spawning tank was used).
This fish does best in a small group, six or more, in a spacious well-planted aquarium with very minimal water movement and subdued lighting; stable water parameters are essential, and the fish should only be introduced to a well-established aquarium. Floating plants are mandatory, both to shade the light and to provide feeding and spawning sites; Ceratopteris (Water Sprite) and Hygrophila difformis (Wisteria) allowed to grow along the surface are ideal.
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 species was first described as Osphromenus vittatus by G. Cuvier in 1831, and moved to the genus Trichopsis [erected by Canestrini in 1860] by K.F. Liem in 1965. The correct spelling of the species name--which is Latin for banded--is vittata, the feminine form to agree with the gender of the genus name. Major changes to the taxonomy of this and related families have occurred, see J.S. Nelson.
Ladich, F., W. Brittinger and & H. Kratochvil, "Significance of Agonistic Vocalization in the Croaking Gourami (Trichopsis vittatus, Teleostei)," Ethology, vol. 90, No. 4 (1992), pp. 307-314.
Ladich, F., "Sound Characteristics and Outcome of Contests in Male Croaking Gouramis (Teleostei)," Ethology Vol. 104 (1998), pp. 517-529.
Liem, Karel F., "The Status of the Anabantyoid Fish Genera Ctenops and Trichopsis," Copeia, Vol. 1965, No. 2 (June 25, 1965), pp. 206-213.
Nelson, Joseph S., "Fishes of the World," 1994 (latest edition now 2006).
Croaking Gourami Diet
Feeds on zooplankton, crustaceans and insect larvae. Accepts most prepared foods; dried foods should be supplemented with frozen daphnia and bloodworms, live artemia (brine shrimps), insects and worms.
Close to 3 inches (7 cm).
Minimum Tank Suggestion
24 inches in length.
Ideal water parameters for Croaking Gourami
Soft to moderately hard (5 to 19 dGH), acidic to slightly basic (pH 6 to 8) water, temperature 22-27C/73-81F.