Known only from a handful of localities in Bangkok, Samut Sakhon, Samut Songkhram and Samut Prakan provinces in central Thailand, all of which lie on the coast of the Gulf of Thailand.
Most habitats are in close proximity to Bangkok, which continues to expand rapidly, are considered under extreme threat, and recent surveys have failed to confirm that the fish is still present in Samut Songkhram and Samut Prakan.
Populations from different localities exhibit slight morphological differences, e.g., the shape of the caudal-fin can vary from rounded to ovate, and should not be mixed or hybridised in aquaria.
Inhabits brackish, frequently tidal, coastal swamps and is often associated with the mangrove palm Nypa fruticans, commonly-known as the nipa palm, the only species of palm specifically adapted to estuarine environments.
Males build their bubble nests between the palm branches or within the bracts at the base of the trees, these providing protection and shelter. Although brackish populations of both B. imbellis and B. splendens have been discovered t’s the only member of the genus to occur exclusively under such conditions.
PH at habitats in Samut Sakhon province varied between 6.87-7.80 with salinity ranging from 1.1-10.6 ppt. Sympatric fish species include Trichopsis vittata, Trichopodus trichopterus, Anabas testudineus, Aplocheilus panchax, Oryzias javanicus, Dermogenys siamensis, Channa striata, and Boraras uropthalmoides.
Temperature: 22 – 28 °C
pH: 7.0 – 8.5
Hardness: 90 – 357 ppm