New Species of Fighting Fish Found in Thailand

A team of biologists has discovered a new species of bubble-nesting fighting fish in Samut Sakhon Province, Thailand.

Male B. mahachaiensis displaying aggression (Chanon Kowasupat et al, Zootaxa)

The new species, called Betta mahachaiensis, belongs to the Betta splendens group in the family Osphronemidae.

B. mahachaiensis has a body length of about 1.4 inches (3.5 cm) and differs from other members of the B. splendens group by an iridescent green/bluish-green appearance on the brown-to-black body background.

The team, led by Dr Chanon Kowasupat of the Mahidol University in Nakhon Pathom, Thailand, describes the species in a paper in the journal Zootaxa: “male with dark-brown to black head, with iridescent green to bluish-green scales. Opercles with two parallel iridescent green to bluish-green vertical bars, opercular membrane brown to black, eyes with iridescent green to bluish-green patches at bottom and posterior regions. Body dark brown to black with iridescent green to bluish-green scales arranged in regular rows, with a similar iridescent area on each scale.”

“Female less colorful: head and body yellowish to light-brown with iridescent green to bluish-green scales; opercles pale gold with two faint iridescent green to bluish-green bars; throat with chin-bar.”

Female B. mahachaiensis (Chanon Kowasupat et al, Zootaxa)

The name mahachaiensis is derived from Thai name for a subdistrict of Samut Sakhon Province – Maha Chai, the site where first specimens of the species were collected.

According to the biologists, the fish inhabits sites with nipa palms and brackish water: “B. mahachaiensis lives in brackish waters, some quite heavily polluted; pH at catch sites 6.87 – 7.80, salinity 1.1–10.6 ppt. The species was found in nipa palm (Nypa fruticans) swamps, especially, in the water-holding phytotelma of the palm bract, which the pair use for bubble-nest building, courtship, and hatching of fry.”

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Bibliographic information: Chanon Kowasupat et al. 2012. Betta mahachaiensis, a new species of bubble-nesting fighting fish (Teleostei: Osphronemidae) from Samut Sakhon Province, Thailand. Zootaxa 3522: 49–60