Classification:
Order: Perciformes
Family: Osphronemidae
Distribution:
Distributed throughout the lower Mekong River basin in Laos, Vietnam, Cambodia, and Thailand, and in watersheds across central and southern (peninsular) Thailand. Type locality is ‘Saigon, southern Vietnam’.
Habitat:
Found in all types of still to slow-moving, predominantly lowland habitat, including swamp forest, peat swamps, floodplains, river tributaries, irrigation canals, paddy fields, and roadside ditches. Displays a distinct preference for sluggish to still environments with dense growths of aquatic or riparian vegetation. Sympatric fish species include Trichopsis vittata, T. schalleri, Trichopodus trichopterus, Betta siamorientalis, Anabas testudineus, Lepidocephalichthys hasselti, Pangio anguillaris, Macrognathus siamensis and Monopterus albus.
Maximum Standard Length:
35 – 40mm.
Aquarium Size:
An aquarium with base measurements of 45 x 30cm or equivalent is large enough to house a pair or small group.
Maintenance:
This species fares best in a well-planted, shady aquarium with plenty of surface cover in the form of tall stem plants, floating varieties, or tropical lilies. Cryptocoryne spp. are also a good choice. Driftwood can also be used and other plants such as Microsorum or Taxiphyllum spp. may be attached to it. Small clay plant pots, lengths of plastic piping or empty camera film cases can also be included to provide further shelter. The addition of dried leaf litter 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, with an air-powered sponge filter set to turn over gently adequate. Keep the aquarium well-covered and do not fill it to the top since it requires occasional access to the layer of humid air that will form above the water surface, and is an excellent jumper.
Water Conditions:
Temperature: 22 – 28°C
pH: 5.0 – 7.5
Hardness: 18 – 215ppm
Diet:
Captive fish will normally accept dried products once they are recognised as edible, but should be offered plenty of small live or frozen foods such as Daphnia, Artemia or chironomid larvae (bloodworm) to ensure development of optimal colour and condition.
Behaviour and Compatibility:
Best maintained in a pair or small group, either alone or with very peaceful, similarly-sized species, since much bigger or more vigorous tankmates are likely to both intimidate and outcompete it. Small, schooling cyprinids such as Microdevario, Boraras, or Trigonostigma spp. make good choices, as do diminutive loaches such as Pangio or Petruichthys.
Sexual Dimorphism:
Can be tricky to sex, but sexually mature males are normally exhibit a more intense colour 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, with the ovaries in females clearly visible below the swim bladder.
Reproduction:
Bubble-nester. Organise a separate tank for breeding purposes unless the fish are already being maintained alone, setting this up as suggested above. It should have the tightest-fitting cover you can find (some breeders use clingfilm instead to ensure no gaps) as the fry need access to a layer of warm, humid air without which development of the labyrinth organ can be impaired. The pair need not be separated prior to spawning. The male may construct the nest in a tube or canister, under a broad plant leaf or among fine-leaved surface vegetation, and will not usually tolerate the female in the vicinity until it is complete. Spawning normally occurrs beneath the nest in an ‘embrace’ typical of osphronemids, with the male wrapping himself around the female. At the point of climax milt and a few eggs are released in a cluster or ‘packet’, which the male collects and transports to the nest. This cycle is then repeated until the female is spent of eggs. Post-spawning the adults can normally be left in situ, although the female is no longer actively involved with the male assuming sole responsibility for guarding and tending the nest. The eggs hatch in 24-48 hours, remaining in the nest for a further 2-3 days until the yolk sac is fully-absorbed, while the male continues to collect and return any that fall. Once the fry begin to swim freely the male will lose interest, but the adults do not usually eat their offspring. They require an infusoria-grade food for the first few days, after which they can accept motile foods such as microworm and Artemia nauplii. Water changes should be small and regular rather than large and intermittent.
