Emerald Betta Care
Betta smaragdina
The emerald betta is a labyrinth fish from still and slow-moving waters of northeast Thailand and Laos. Its iridescent scales are distinctive, but ornamental line-breeding and hybridisation mean trade fish are not automatically pure wild forms. The species jumps well, needs an air space above the water and is not recommended by the specialist source for a standard community aquarium. A planted, calm setup with cover and carefully selected tankmates supports good care. This guide covers aquarium setup, water, diet, behaviour and breeding.
Plan your aquarium →At a glance
- Temperature
- 22–28 °C
- pH
- 5.5–7.5
- GH
- 1–10 °dGH
- Aquarium length
- At least 45 cm
- Minimum aquarium volume
- At least 41 L
- Adult size
- Up to 6 cm
- Group size
- At least 2 individuals
- Temperament
- Territorial
About this species
Betta smaragdina Ladiges, 1972 belongs to Osphronemidae. It comes from the Khorat Plateau in eastern Thailand and Mekong tributaries in Laos. Its labyrinth organ helps it use atmospheric air. Males are generally more colourful and develop longer fins. Trade lines have been selectively bred and sometimes hybridised, so colour form alone cannot confirm a wild locality.
Natural habitat
The emerald betta inhabits rice paddies, swamps, ditches and other still or sluggish lowland waters. Vegetation provides cover and nesting sites. FishBase reports ecological observations across a broad pH and hardness range; isolated field measurements are not automatically aquarium advice. In captivity, stable, clean water and gentle flow with sheltered areas are important.
Aquarium and layout
Seriously Fish recommends a minimum 45 × 30 cm footprint, about 41 litres, for a pair. Plant the aquarium densely with wood, leaves and sheltered areas. Floating plants can soften light and support nest building. Use gentle filtration and secure the lid: this betta can jump and needs access to the air layer above the water. Do not fill the tank to the rim.
Water conditions
For aquarium care, Seriously Fish gives 22–28 °C, pH 5.5–7.5 and hardness 1–10 dGH. FishBase lists environmental data of 24–27 °C, pH 6–8 and hardness 5–19; these are not directly equivalent aquarium recommendations. Use the specialist husbandry range and avoid rapid changes. Ask about the fish’s origin and previous water conditions.
Behaviour and group size
This species is not recommended for a standard community aquarium. Seriously Fish advises keeping it alone or only with very peaceful species after careful research. Males may be territorial, and lines selected for fighting can show stronger aggression. Allow for individual variation and provide cover that breaks line of sight. A pair is not automatically safe; have a way to separate the fish.
Feeding
In the wild, the species eats small invertebrates. Captive fish can learn to accept dried foods, with small live or frozen foods such as Daphnia, Artemia or mosquito larvae as supplements. Offer mouth-sized portions and check that every fish eats. Avoid overfeeding, as bettas can be prone to weight gain.
Breeding
The emerald betta builds a bubble nest. The male guards it and may chase the female after the nest is complete. Provide floating plants and dense cover. A tight-fitting lid keeps the air layer warm and humid, which matters for fry development. Free-swimming fry first need very fine food such as infusoria. Breeding requires separate space and close observation of the female.
Sources & review
This care guide draws on several specialist sources and was last checked on .