Not furry, but we like them anyway.
Emerald Betta
Betta smaragdina Ladiges, 1972
Also called Blue betta, Mekong fighting fish, Emerald green betta
From Mekong and Chao Phraya river basins of Thailand and Laos, especially the Khorat Plateau (Isan) of north-eastern Thailand.123
A friendly guide, not veterinary advice. For anything about your pet's health, ask your vet.
At a glance the quick version
Seriously Fish gives 60 mm standard length; FishBase gives 7 cm total length.
Looks how to spot one
Scales, slender labyrinth fish
A short-finned wild betta with a sturdy build. Its emerald and blue shine comes from tiny light-reflecting crystals in the skin. It breathes air at the surface using a labyrinth organ.13
Personality what they are like
Males are territorial with one another, but with lots of cover several can live together. Females are calmer.2
Daily activity how busy a day looks
Calm swimmer that prefers still or slow water with plants.23
Grooming and care the hands-on bits
Use a tight lid and keep warm, humid air above the water surface. Keep water clean with gentle filtration.21
Home where they are happiest
A tank of roughly 40 litres (45 x 30 cm base) for a pair. Temperature 22-28 C (FishBase gives 24-27 C), pH 5.5-7.5 (FishBase gives 6.0-8.0), soft to moderately hard water. Dense plants, floating cover and leaf litter suit it.21
Food basics what goes in the bowl
Small invertebrates in the wild. In the aquarium it takes dried food plus regular live or frozen daphnia, brine shrimp or bloodworm.23
Company who they like around
Best kept alone or as a pair, or in a species tank with plenty of hiding places; not a typical community fish.2
The story where it all began
Described by Ladiges in 1972 from Nong Khai in north-eastern Thailand. In Thailand it has been line-bred for generations, and it is also selectively bred for the ornamental trade, giving several colour forms.123
Fun facts for the dinner table
- 1
Its green and blue glow is structural colour, made by hexagonal crystals smaller than half a micrometre that bend and reflect light.3
- 2
A natural colour form called Guitar, with distinctive fin markings, comes from north-eastern Thailand.3
- 3
Its Thai name translates roughly as green fighting fish.3
- 4
The male builds a bubble nest and guards the eggs and fry.2
Recognised by the official bits
- IUCN Red List
- Data Deficient (assessed 19 January 2011)1
- Taxonomy
- Family Osphronemidae; described by Ladiges in 1972; type locality Nong Khai, Thailand2
The care rhythm Furry Diary remembers it for you
A typical home-care rhythm for a Emerald Betta. It is our own starting plan, not a vet's advice, and you can change every line in the app.
- Feedingevery day
- Temperature checkevery day
- Water changeAbout 25% of the waterevery week
- Water testevery week
- Filter rinseevery month
Owner questions the things everyone asks
How often should I feed my Emerald Betta?
Feed your Emerald Betta once a day, offering only what it can eat in a couple of minutes. Furry Diary's starting plan suggests daily feeding. Adjust the amount based on the food label and your vet's advice.2 Furry Diary plan
What does an Emerald Betta eat, and what should it never eat?
In the wild it eats small invertebrates. In the aquarium, give dried food plus regular live or frozen daphnia, brine shrimp or bloodworm. Never feed it anything that is not specifically for fish, and avoid overfeeding.23
How much space does an Emerald Betta need?
A pair needs a tank of roughly 40 litres (45 x 30 cm base). Provide dense plants, floating cover and leaf litter. More space is always better for their comfort.21
What temperature, light or water does an Emerald Betta need?
Keep the water temperature between 22-28°C (24-27°C per FishBase), pH 5.5-7.5 (6.0-8.0 per FishBase), and soft to moderately hard water. Use gentle filtration and maintain warm, humid air above the water surface. Furry Diary's plan includes daily temperature checks.21 Furry Diary plan
How often should I clean an Emerald Betta's home?
Furry Diary's starting plan suggests a weekly water change of about 25% and a weekly water test. Rinse the filter every 30 days. Always use a dechlorinator and match the new water temperature. Furry Diary plan
Can an Emerald Betta live with others?
Males are territorial with each other, but with lots of cover several can live together. Females are calmer. Best kept alone, as a pair, or in a species tank with plenty of hiding places. Not a typical community fish.2
How long does an Emerald Betta live?
Lifespan varies depending on care, genetics and environment. For a more accurate estimate, ask a good breeder or an exotic-pet vet.
Can I handle an Emerald Betta?
It is best not to handle your Emerald Betta. It is a calm swimmer that prefers still or slow water with plants, and handling can stress or injure it. Use a net only when necessary.23
Written from the sources on this page, a few checked guides (VCA, ASPCA, RSPCA) and Furry Diary's own starting care plan. A friendly guide, not a vet's advice.
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Where this comes from
Every breed page shows where each fact comes from. If we got something wrong, sorry, we are pet people, not a science magazine. Tell us at support@furrydiary.app and we will fix it.
- FishBase: Betta smaragdina summary fishbase.seused for origin, size, water parameters, IUCN status, colours
- Seriously Fish: Betta smaragdina seriouslyfish.comused for care, tank size, diet, behaviour, type locality
- Wikipedia: Betta smaragdina en.wikipedia.orgused for other names, colour science, varieties
- VCA Animal Hospitals: Feeding times and frequency for your dog vcahospitals.comused for owner questions
- ASPCA: Dog grooming tips aspca.orgused for owner questions
- ASPCA: Cat grooming tips aspca.orgused for owner questions
- ASPCA: People foods to avoid feeding your pets aspca.orgused for owner questions
- RSPCA: What to feed your rabbit rspca.org.ukused for owner questions
Checked 2026-09-30. Text is written in our own words from these sources.