Not furry, but we like them anyway.
Turquoise Rainbowfish
Melanotaenia lacustris Munro, 1964
Also called Lake Kutubu rainbowfish
From Papua New Guinea (Southern Highlands Province): found only in Lake Kutubu and its outflow, the Soro River, in the Kikori River system.123
A friendly guide, not veterinary advice. For anything about your pet's health, ask your vet.
At a glance the quick version
Standard length: FishBase gives 10 cm, Seriously Fish 12 cm
Looks how to spot one
Scaled, laterally compressed rainbowfish
A torpedo-shaped fish when young; adult males grow much deeper in the body than females and become the brightest of the pair. Breeding males show an orange patch just above the gill covers. Young fish in shops look fairly plain and take a year or more to reach full adult colour.1
Personality what they are like
A peaceful, busy schooling fish that gets along with most similar-sized tankmates, though its energy can unsettle very small or slow fish.12
Daily activity how busy a day looks
An active open-water swimmer that needs a long tank with clear swimming lanes alongside planted areas.1
Grooming and care the hands-on bits
Plant the tank well and keep the water flow gentle. Be patient with juveniles: the full adult colour can take over 12 months to appear.1
Home where they are happiest
Minimum tank about 120 x 30 x 30 cm (around 108 litres). Temperature 20-25 °C, pH 7.0-9.0 (FishBase gives 7.0-8.0), hardness roughly 9-20 dGH. A planted layout with rocks and driftwood suits it.12
Food basics what goes in the bowl
Omnivore. Accepts dried, frozen and live foods; a varied diet keeps it in good colour.12
Company who they like around
Keep a group of at least 6-8; larger shoals look and behave best.1
The story where it all began
Munro described the species in 1964 from Lake Kutubu, a highland lake in Papua New Guinea that formed when volcanic debris dammed a valley. It has since become an established aquarium fish and is bred commercially for the hobby.213
Fun facts for the dinner table
- 1
It lives naturally in only one lake and its outflow river, and nowhere else in the world.3
- 2
Lake Kutubu has many fish found only there; Seriously Fish counts 10 of its 14 native species as endemic.1
- 3
Juveniles are often sold as plain 'blue' rainbowfish and only reveal their full turquoise sheen after about a year.1
- 4
Pairs show distinct pairing behaviour when spawning.2
Recognised by the official bits
- IUCN Red List
- Endangered (assessed December 2019); an older listing cited by Seriously Fish gives Vulnerable2
- Taxonomy
- Family Melanotaeniidae; described by Munro in 19642
The care rhythm Furry Diary remembers it for you
A typical home-care rhythm for a Turquoise Rainbowfish. It is our own starting plan, not a vet's advice, and you can change every line in the app.
- FeedingSmall amounts once or twice a dayevery day
- Temperature checkevery day
- Water changeAbout 25% of the waterevery week
- Water testevery week
- Glass cleanevery week
- Filter rinseRinse in old tank water, never tap waterevery month
Owner questions the things everyone asks
How often should I feed my Turquoise Rainbowfish?
Feed small amounts once or twice a day. A varied diet keeps it healthy and colourful. Check the food label for portions and adjust as needed.12 Furry Diary plan
What does a Turquoise Rainbowfish eat, and what should it never eat?
As an omnivore, it enjoys dried, frozen and live foods. Specific foods to avoid are not listed here, so please ask your vet or a good breeder for guidance.12
How much space does a Turquoise Rainbowfish need?
A minimum tank of about 108 litres (120 x 30 x 30 cm) is recommended. A longer tank with clear swimming lanes suits its active nature best.1
What temperature, light or water does a Turquoise Rainbowfish need?
Keep water temperature between 20-25°C, pH 7.0-8.0 (up to 9.0 is possible), and hardness 9-20 dGH. Light needs vary; a planted setup with moderate light works well, ask your breeder for specifics.12
How often should I clean a Turquoise Rainbowfish's home?
Furry Diary's starting plan suggests a 25% water change and glass cleaning weekly, plus a monthly filter rinse in old tank water. Regular water testing helps keep conditions stable. Furry Diary plan
Can a Turquoise Rainbowfish live with others?
Yes, it is a peaceful schooling fish that gets along with most similar-sized tankmates. Keep it in a group of at least 6-8, and avoid very small or slow fish that it might unsettle.12
How long does a Turquoise Rainbowfish live?
Lifespan varies and is not specified in the information available. For an accurate estimate, please consult your breeder or an exotic-pet vet.
Can I handle a Turquoise Rainbowfish?
Handling fish is generally not recommended as it causes stress. This specific need is not covered in the provided information, ask your vet or a good breeder for advice.
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.
You might also like
Boeseman's Rainbowfish
Banded Rainbowfish
Murray River RainbowfishLike what we are building? Buy Archy a bone.
All of this is free for everyone, with a source on every fact, and it will never show annoying ads. It was a big job to build, so if it helped you, buy Archy a bone. Any amount is lovely, and no is a perfectly fine answer too.
Archy is our Australian Cattle Dog and chief taste tester. Tips go to 4V3D OÜ, the small family studio behind Furry Diary.
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.
- Seriously Fish: Melanotaenia lacustris (Lake Kutubu Rainbowfish) seriouslyfish.comused for habitat, size, tank size, water parameters, diet, group size, dimorphism, colour development, endemism
- FishBase: Melanotaenia lacustris, Lake Kutubu rainbowfish fishbase.seused for author and year, distribution, max length, water ranges, IUCN status, behaviour
- Wikipedia: Lake Kutubu rainbowfish en.wikipedia.orgused for other names, endemism, IUCN status
- 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.