Taxonomy & naming
Betta livida was formally described by Peter Ng and Maurice Kottelat in 1992, based on specimens collected from a blackwater stream in the north Selangor peat swamp forest, approximately 800 metres from the 45-kilometre mark on the road between Tanjong Malim and Sungai Besar. The holotype is held at the Zoological Reference Collection, National University of Singapore (ZRC 15287), with paratype material deposited at several Malaysian institutions.
The species belongs to the coccina group, a cluster of small, red-bodied Betta from the peat swamp forests of Sundaland. The valid name as listed in Eschmeyer's Catalog of Fishes is Betta livida Ng & Kottelat, 1992. Within the coccina group, B. livida is most readily distinguished from B. coccina by the presence of the lateral iridescent green spot in both sexes (in B. coccina the spot occurs only in males), and by the green-tipped pelvic fins (black-tipped in B. coccina). Two vertical gold bars on the operculum are also characteristic. Like all members of the genus, B. livida is a labyrinth fish, possessing the suprabranchial organ that allows direct aerial respiration.
Morphology
Betta livida is a small fish, reaching a maximum of approximately 1.5 in standard length. The body is elongate and laterally compressed in the typical Betta form. Base coloration in adults is a rich red-brown to dark red, deepening toward the dorsal surface. The most distinctive marking is a lateral iridescent green spot or blotch on the flank, present in both sexes — a consistent character that aids identification in the field and in the aquarium.
Sexual dimorphism is moderate. Males are more intensely coloured, with more elaborate, extended fins, and the green lateral spot is typically bolder and more iridescent. Females are rounder in the abdomen, somewhat duller in overall coloration, and show a visible ovipositor (egg tube). Both sexes carry the green-tipped pelvic fins. The iridescent green spot is reported to diminish or disappear with age in males, a point worth noting when assessing older individuals.
Habitat
Betta livida is a stenotopic peat swamp specialist — it is essentially unknown outside intact or near-intact lowland peat swamp forest within a very small area of Peninsular Malaysia, centred on northern Selangor and extending into southern Perak. The type locality is a blackwater stream in the north Selangor peat swamp, and the species has been documented from only a handful of sites within an estimated extent of occurrence of around 3,31 mi².
The water it inhabits is genuinely extreme by the standards of most tropical fishes: tea-dark with dissolved tannins and humic acids, very soft, and acidic. Recorded pH values range from approximately 3.0 to 6.0 across different localities, with measurements as low as 3.5 to 3.7 at some sites and 4.5 to 5.5 at others. Temperature in the field ranges from roughly 72–81 °F. Water depth is typically shallow — generally less than a metre in the still pools, shallow drainage ditches, and vegetated stream margins the species occupies. The substrate is leaf litter and detritus. The labyrinth organ is critical in this environment: still, shaded, oxygen-depleted peat water requires an air-breathing supplement to gill respiration, and access to the water surface is essential.
Feeding
In nature, Betta livida is an insectivore and invertebrate predator, feeding on small insects, insect larvae, and other invertebrates encountered among the leaf litter and at the water surface in its peat swamp habitat. The species is opportunistic, taking prey of an appropriate size from whatever the water and its margins make available.
In captivity, live and frozen small foods are strongly preferred. Bloodworm, Daphnia, and Artemia (brine shrimp) are all accepted; some individuals are reluctant to take frozen bloodworm and do better on live or live-then-frozen transitions. The species has been described as a live-food preference fish, and offering a variety of small live invertebrates regularly will maintain condition and breeding readiness. Dry or prepared foods are generally taken only reluctantly, if at all, and should not form the staple diet.
Mating
Betta livida is a bubble-nester. The male constructs a nest of mucus-bound bubbles, typically positioned in an enclosed space — under a broad leaf, within aquatic vegetation, or inside a tube or cavity at or just below the water surface. In captivity, artificial sites such as a small floating tube or a black film canister placed at the surface are readily adopted. The nest serves as the site for spawning and the subsequent rearing of eggs and larvae.
Courting males display their coloration intensely before a receptive female. Spawning occurs in the typical osphronemid embrace, the male curling around the female as she releases eggs. The eggs, once fertilised, are gathered by the male and placed in the bubble nest. Wild-caught and captive individuals have been observed as seasonal spawners, with spawning activity noted particularly from September through March, though in stable captive conditions pairs will spawn year-round.
Breeding
After spawning, the male assumes sole responsibility for the nest and its contents, collecting any falling eggs and repairing the bubble raft as needed. Clutch size is typically 20 to 50 eggs. Incubation is relatively brief: eggs begin hatching within approximately 24 to 48 hours, and the larvae become free-swimming around 3 to 4 days after hatching. The male continues to guard the fry and return any that stray from the nest area during this period.
Fry are very small at the free-swimming stage and require appropriately tiny first foods — infusoria, commercially prepared rotifers (APR), or similar live microorganisms. By the second week, the fry are generally large enough to accept newly hatched brine shrimp nauplii. Unusually low levels of sibling cannibalism have been noted in captive broods, and the parents have been observed to coexist with free-swimming fry without significant predation. In captivity, paired individuals are long-lived, with pairs documented spawning productively for more than three years.
In the aquarium
Betta livida is a shy, light-sensitive species that does best in a quiet, dimly lit aquarium with abundant cover. A single pair can be maintained in a tank as small as 5 gallons; groups of multiple pairs or a species community require a larger tank of 20 gallons or more, with adequate territorial boundaries provided by dense planting and sight-breaks. The species is not suited to a brightly lit, busy community tank.
Water quality is non-negotiable for this peat swamp endemic. The aquarium should be set up with reverse-osmosis or rainwater conditioned with peat extract or similar tannin source to achieve the soft, acidic conditions the species requires: pH in the range of 3.5 to 5.5, very low hardness, and temperatures in the low-to-mid 20s Celsius (not exceeding approximately 75 °F per some guidelines, though the natural range extends to 81 °F). Biweekly partial water changes using water of the same chemistry are recommended, keeping conditions stable rather than performing large disrupting changes. Substrate of dried leaf litter — oak or Indian almond leaves — and planting with Java moss and Java fern complete the biotope. Filtration should produce minimal flow; the labyrinth organ requires unobstructed access to the air above the water surface, and a tight-fitting lid helps maintain warm, humid surface air. Live food is important for long-term health and breeding condition.
Conservation
Betta livida is assessed as Endangered (EN) under criterion B1ab(iii) on the IUCN Red List, an assessment published in 2019 (with the assessment date of 28 December 2018). The primary justification is a restricted extent of occurrence estimated at approximately 3,31 mi² — well below the 5,0 mi² threshold — combined with presence in only four threat-defined locations and a continuing decline in the extent and quality of its peat swamp forest habitat.
The overwhelming driver of population decline is large-scale conversion of lowland peat swamp forest to industrial monoculture, particularly oil palm and pulp plantations, across Selangor and Perak. This transformation eliminates the specific hydrological and chemical conditions on which B. livida depends: once peat swamp forest is drained and cleared, the blackwater chemistry that defines the species' niche cannot be reconstructed. The species appeared in the aquarium trade at least as of 2016, which creates some additional collection pressure on already small and isolated populations. Conservation research priorities identified in the IUCN assessment include clarifying the species' full distribution, monitoring population trends, establishing area-based management plans, and expanding habitat protection for the remaining peat swamp forests of northern Selangor. Hobbyist captive-breeding programmes have maintained the species in cultivation and reduce the need for wild collection; sourcing captive-bred stock remains the most direct positive action an aquarist can take.