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Encyclopedia / Gouramis & Bettas / Emerald betta
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Variations

2 kinds · tap one for a closer look

Emerald betta

Betta smaragdina · Isan betta, Betta smaragdina, Green betta

Like splendens it is aggressive between males; one male can be kept with several females in a planted tank.

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7 cmAdult size ✓
24–28 °CTemperature ✓
6–7.5pH ✓
40 LSmallest tank ✓
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Tank mates
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Not recommended
  • White cloud mountain minnow needs cool water and makes a lot of waste, while Emerald betta is tropical.
  • They need different temperatures (24–28 °C vs 14–22 °C). No setting suits both.
Not recommended
  • Giant gourami eats animals up to about 10 cm. Emerald betta only grows to 7 cm.
Not recommended
  • They need different temperatures (24–28 °C vs 10–22 °C). No setting suits both.
With conditions
  • Only a narrow temperature range suits both: 24–25 °C.
With conditions
  • Only a narrow temperature range suits both: exactly 24 °C.
Compatible
Compatible
Compatible
Compatible
Compatible

336 species in our list are a good match.

Facts checked against sources on 16 Oct 2026. ✓ means a source backs it; ? means no reliable source yet. See sources

Care and water

Hardness ✓1–10 dGH
Group size ✓2 or more
Temperament ?Semi-aggressive
Swims at ?Top
Care level ✓Moderate
Diet Carnivore
Lifespan ?Unknown
Size in shops 3–5 cm
Growth Medium

Behavior

Like splendens it is aggressive between males; one male can be kept with several females in a planted tank. Calm with other peaceful fish.

Food

Frozen and live foods; some micro-pellets.

Tap a food to see what it is.

Male or female

Males are more colourful (reddish-brown with an iridescent blue or green spot on each scale, blue fins with red rays) and grow longer fins; females are brown with two darker stripes.

Health

Common problems. Tap one to see the signs. This is a guide, not a diagnosis.

Breeding

Bubble-nester · Easy

Bubble nester: the male builds the nest, places the eggs in it and guards it alone.

Pairing

Condition a pair separately and introduce the female to the male's nest.

Setup

30 L planted tank with floating plants and a gentle sponge filter.

What starts it

Live foods and warm water.

Eggs

Egg count not found in sources. Eggs hatch in 24-48 hours; fry stay in the nest 3-4 more days.

Raising the fry

Infusoria then baby brine shrimp; the male guards the fry.

Common mistakes
  • Leaving the female in with the male
  • Fast flow
  • Cool water
Full breeding guide, day-by-day plan and simulator →

Where it lives in the wild

RegionNorth-eastern Thailand & Laos
Rivers and lakesMekong basin (Khorat Plateau)
HabitatShallow ponds, rice fields and swamps
Native rangeAbout 400 km across
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The story of the emerald betta

A bubble-nesting betta from the Khorat Plateau of north-east Thailand and Mekong tributaries in Laos; 'smaragdina' is Latin for emerald-coloured, after the male's iridescent green scales. Line-bred for fighting in Thailand and bred into colour forms for the trade.

Werner Ladiges described the emerald betta in 1972. A close relative of the Siamese fighting fish, it is admired for its green-blue scales and is now also bred in colour forms.

First described by Werner Ladiges in 1972. Named for 'Smaragdina' means emerald-coloured.

  • It belongs to the same species group as Betta splendens.
  • Its scales shine green like emeralds.
  • Males build bubble nests and guard the eggs.

Sources

14 facts checked with sources