Emerald betta
Betta smaragdina
intermediate careOverview
The emerald betta (Betta smaragdina), sometimes called the guitar or blue betta, is a wild member of the Betta splendens complex from the Khorat Plateau of northeast Thailand and Laos. Its scales shimmer emerald-green and blue over a dark body, with red-and-green banded fins — a subtler, wilder beauty than a fancy betta. Compact, hardy for a wild betta and full of character, it is a superb introduction to keeping wild Betta species.
Tank & water
A single fish is happy in 19–38 litres; a pair wants 38 litres (10 gallons) or more, densely planted.
- Temperature: 24–28 °C from a small heater — it is a warm tropical fish.
- Water: soft to neutral, pH 6.0–7.5; it is fairly adaptable but dislikes hard, alkaline extremes. Test with a kit.
- A tight lid: an air-breather and a jumper — always cover the tank.
- Planted with cover: floating plants, broad leaves and leaf litter give security and break up sightlines.
Feeding
The emerald betta is a carnivorous micropredator. It usually accepts a quality betta pellet but colours up best on small live and frozen foods — bloodworm, daphnia, brine shrimp and mosquito larvae. Feed small portions once or twice a day and avoid overfeeding, the most common cause of poor water in betta tanks.
Behaviour & tankmates
This is a territorial labyrinth fish. House one male alone, or a compatible bonded pair with plenty of cover. In a large, heavily planted tank a pair can share space with peaceful nano fish such as small rasboras, ember tetras or pygmy corydoras, but never with another betta or with fin-nippers. Watch your individuals — temperament varies. For more on mixing, see can a betta live with other fish.
A bonded pair will often build a bubble nest under a floating leaf, with the male tending the eggs and fry, so a quiet, well-planted tank gives the best chance of seeing this behaviour. Keep the lid tight and the surface calm, as the labyrinth organ means they must breathe warm, humid air from the top.
Give the emerald betta soft-to-neutral, warm, stable water and the odd live treat, and it rewards you with all the personality of a betta in its natural, wild-caught colours — see our best nano aquarium picks.
Emerald betta — frequently asked questions
How is Betta smaragdina different from a normal betta?
The emerald betta is a wild species in the Betta splendens group, so it shares the same general care but keeps a compact, streamlined wild body and shimmering green-blue scaling rather than the long, flowing fins of show bettas. It is a bubble-nester like the common betta, not a mouthbrooder.
Can emerald bettas be kept in a community tank?
Cautiously. A single fish, or a pair in a large planted tank, can share space with small, peaceful, non-nippy nano fish. Males remain territorial and must never be housed with another betta, and shy tankmates suit them better than fast, boisterous ones.
What water does the emerald betta prefer?
Soft to neutral, stable water around pH 6–7.5, warm and gently filtered. It comes from shallow, plant-choked pools and rice paddies in Thailand and Laos, so it appreciates dense planting, surface cover and calm water more than a specific number on a test kit.
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