Mahachai Betta

The Mahachai betta is a short-finned species closely related to the Siamese fighting fish and was scientifically described in 2012; before that it was known in the hobby as "Betta sp. Mahachai" and thought to be a local form of one of its related species. It is named after the town of Mahachai, known as the center of Samut Sakhon province. The males' very dark body is covered with rows of bright green-turquoise scales.

In the wild it is found only along a small coastal strip west of Bangkok. Because this area is changing rapidly due to industry, urbanization and aquaculture farms, the species is seriously threatened. In this respect it is important to choose captive-bred fish and keep the line pure.

It lives in nipa palm swamps near the coast, in tidally influenced, slightly brackish (low-salinity) water. Males often build their bubble nests inside or under fallen palm fronds and stems. The water is warm, still and rich in organic matter.

• Volume: at least 40 liters for a pair; 60 liters is more comfortable.
• Water: 26–29°C, pH 6.5–8. It does fine in fresh water in the aquarium; adding a small amount of salt is optional and unnecessary if it is kept with freshwater tankmates.
• Decor: dense plants, floating plants, dried leaves, and tubes or small caves that can be used as nest sites.
• Flow: very weak; a sponge filter is ideal.
• Lid: it jumps well; a tight lid and a warm air space above the surface are needed.

Carnivorous. It accepts small granules and flakes; supplement with frozen or live bloodworms, brine shrimp, daphnia and mosquito larvae. Feed 1–2 times a day, as much as is eaten within a few minutes.

Males are aggressive toward each other; two males should not be kept in the same tank. It is generally calm with other species but may see long-finned, colorful fish as rivals. It eats shrimplets.

Good companions: harlequin rasbora, pencilfish, small tetras, kuhli loach, otocinclus, corydoras, nerite snails.

Avoid: a second male of its own species, Siamese fighting fish and other wild bettas (they can hybridize), long-finned fish, fin nippers, gouramis.

A single male is kept, alone or with 1–2 females. Females need planted areas where they can hide. Because it is an endangered species, take care that it does not hybridize with other bettas; pair only fish of the same species and known origin.

The male usually builds his bubble nest in a sheltered spot such as a tube, under a leaf or in a cave. He collects the eggs released during the embraces with his mouth, places them in the nest and guards them. The female should be removed after spawning. The eggs hatch in 1–2 days; the fry start on infusoria and microworms, then eat brine shrimp nauplii. Young males should be separated as they mature.

Hardy. Fin rot can occur in dirty water, and ich and velvet in cold water. Stable, warm water, weekly water changes of 20–25% and quarantine for new fish are the best protection.

Males have a very dark body, dense green-turquoise scales and longer fins; there are bright green markings on their gill covers. Females are light brown with horizontal dark stripes and short fins; their shiny scales are sparse, and an egg spot may be visible under the belly.