1 kinds · tap one for a closer look
Males are aggressive toward each other; keep as a single male or a pair.
310 species in our list are a good match.
Males are aggressive toward each other; keep as a single male or a pair. Tolerates slightly brackish water.
Frozen bloodworms, brine shrimp and live foods.
Tap a food to see what it is.
Males are more colourful (iridescent green to blue-green on a brown-black body, two green bars on the gill cover) and grow longer fins than females.
Common problems. Tap one to see the signs. This is a guide, not a diagnosis.
Bubble-nester · Moderate
Bubble nester: in the wild the pair nests in water held in the leaf bracts at the base of nipa palms; the male guards the nest alone.
A conditioned pair, introduced under supervision.
30 L tank with floating plants and lightly brackish water (SG 1.003-1.005 optional).
Live foods and warm water.
Egg count not found in sources. Eggs hatch in 24-48 hours; fry stay in the nest 3-4 more days.
Infusoria then baby brine shrimp.
A betta from brackish nipa palm swamps near Bangkok, named after Maha Chai subdistrict in Samut Sakhon province. Once thought to be a hybrid, it was shown to be distinct in 2010 and formally described in 2012. It is the only betta found exclusively in brackish water and is part of the Betta splendens complex.
This betta was known to local fish keepers for years before Thai scientists described it in 2012. It lives in a small coastal area near Mahachai, close to Bangkok.
First described by Kowasupat, Panijpan, Ruenwongsa & Sriwattanarothai in 2012. Named for Named after Mahachai, Samut Sakhon, Thailand.
14 facts checked with sources
Valid. Global IUCN: Not Evaluated (FishBase, Red List v2025-2). Wikipedia calls it 'critically endangered (CR) in the IUCN red list' but cites the national Thailand Red Data book (ONEP 2017), so that is a national, not global IUCN, listing. Trade warning: probably hybridised with B. splendens, B. imbellis and B. smaragdina (Seriously Fish); formerly sold as 'Betta sp. Mahachai'.
Eschmeyer's Catalog of Fishes: Betta mahachaiensis (updated 21 Sep 2026) · FishBase: Betta mahachaiensis summaryLegacy has no family field; sourced value recorded.
FishBase: Betta mahachaiensis summarySeriously Fish 6 cm SL (larger, live-adult figure, used); FishBase 4.4 cm SL from the type series. Wikipedia 5-6 cm.
Seriously Fish: Betta mahachaiensis · FishBase: Betta mahachaiensis summaryLegacy 24-29 exceeds the Seriously Fish maximum of 28.
Seriously Fish: Betta mahachaiensisSeriously Fish 7.0-8.5 for aquaria; FishBase (habitat measurements) 6.9-7.8. Legacy 6.5-8 goes too low.
Seriously Fish: Betta mahachaiensis · FishBase: Betta mahachaiensis summaryLegacy has no hardness; Seriously Fish value recorded.
Seriously Fish: Betta mahachaiensis45 x 30 x 30 cm = 40.5 L; legacy 40 L matches.
Seriously Fish: Betta mahachaiensisSeriously Fish: best as a pair. Legacy 1.
Seriously Fish: Betta mahachaiensisLegacy care 2 = moderate.
Seriously Fish: Betta mahachaiensisLegacy has no range field. Seriously Fish: recent surveys failed to confirm it still occurs in Samut Songkhram and Samut Prakan. Habitat salinity 1.1-10.6 ppt.
Seriously Fish: Betta mahachaiensis · Eschmeyer's Catalog of Fishes: Betta mahachaiensis (updated 21 Sep 2026)Legacy 'slimmer male / rounder female' not stated by sources but is not contradicted.
Seriously Fish: Betta mahachaiensis · FishBase: Betta mahachaiensis summaryBubble-nester, not mouthbrooder. Legacy "similar to splendens" is fair.
Seriously Fish: Betta mahachaiensis · FishBase: Betta mahachaiensis summaryLegacy 100-300 eggs not found in a source; hatch time added.
Seriously Fish: Betta mahachaiensisLegacy 'recognised as a separate species in 2012' supported (formal description 2012; molecular evidence by Sriwattanarothai et al. 2010). Legacy 'mangrove canals' is close: the habitat is nipa (mangrove) palm swamp.
Seriously Fish: Betta mahachaiensis · Eschmeyer's Catalog of Fishes: Betta mahachaiensis (updated 21 Sep 2026) · FishBase: Betta mahachaiensis summary