Emerald Betta

The emerald betta is a short-finned wild species related to the Siamese fighting fish. It is named for the shiny emerald green scales that cover its dark body like a net; as the angle of light changes, the green shifts to blue and turquoise. It lacks the long fins of domestic bettas, and its body is longer and sturdier; it grows to 6–7 cm.

Unlike the peaceful betta, its males are clearly aggressive toward each other; in this respect it is close to the Siamese fighting fish, and the one-male rule must be observed. It is easy to care for and a good species for getting started with wild bettas.

It lives in the Isan region of northeastern Thailand and in Laos, in shallow rice paddies, swamps and ponds of the Mekong basin. In the dry season the water level drops very low; with the rains it spreads over wide areas. The waters are warm, vegetated and still.

• Volume: at least 40 liters for a pair; 60 liters, which gives the females hiding space, is better.
• Water: 25–28°C, pH 6–7.5; soft to moderately hard water.
• Plants: dense plants, floating plants, roots and dried leaves.
• 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 readily accepts small granules and flakes; supplement with frozen or live bloodworms, brine shrimp, daphnia and mosquito larvae. Feed small amounts 1–2 times a day; avoid overfeeding.

Males are aggressive toward each other; two males in the same tank will fight. It is mostly calm toward other species but may mistake long-finned, colorful fish for rivals. It eats shrimplets; some individuals also hunt adult dwarf shrimp.

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

Avoid: a second male of its own species, Siamese fighting fish (they hybridize), long-finned fish such as guppies, fin nippers, gouramis.

A single male is kept, alone or with 1–2 females. Females are more docile but still need hiding places. Keeping the male with a female in a small aquarium for a long time can wear the female out; plants and visual barriers are essential. Because it hybridizes with the Siamese fighting fish, do not keep the two species together.

The male builds a bubble nest at the surface; it may be smaller than that of the Siamese fighting fish. He collects the eggs released during the embraces with his mouth, carries them to 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 start attacking each other as they mature and need to be separated.

As a species of wild origin, it is hardy. Fin rot can occur in dirty water, and ich and velvet in cold water. A stable temperature, weekly water changes of 20–25% and warm air kept in by a lid keep it healthy.

Males have dense emerald green scales and longer, more colorful fins; they flare their gill membranes when they see a rival. Females are pale brown with horizontal dark stripes and short fins; they have few shiny scales, and an egg spot may be visible under the belly.