Not furry, but we like them anyway.
Dwarf Neon Rainbowfish
Melanotaenia praecox (Weber & de Beaufort, 1922)
Also called Dwarf rainbowfish, Neon rainbowfish, Diamond rainbowfish, Praecox rainbowfish, Peacock rainbowfish
From Mamberamo River system in northern West Papua (New Guinea), Indonesia.1234
A friendly guide, not veterinary advice. For anything about your pet's health, ask your vet.
At a glance the quick version
Usually up to about 5 cm standard length; occasionally up to 8 cm.
Looks how to spot one
Scales, compact rainbowfish
A small, deep-bodied rainbowfish; males develop a tall body even at only 3 to 3.5 cm. The scales give an iridescent neon-blue shine.134
Personality what they are like
Very peaceful and a little shy, becoming bolder in a group. Males spar and display to each other without real harm.23
Daily activity how busy a day looks
Lively swimmer that stays near the upper water layers and appreciates open space.32
Grooming and care the hands-on bits
Keep a lid on the tank because it can jump. Regular water changes and some live food help colour.32
Home where they are happiest
Minimum about 60 x 30 x 30 cm (around 54 litres). Temperature 22-29 C (sources vary: 22-28 C FishBase, 23-28 C Seriously Fish, 24-29 C ANGFA), pH 6.6-8.0, moderately hard water (about 5-15 dGH). Plenty of plants, including floating plants.2143
Food basics what goes in the bowl
Omnivore that accepts dried, frozen and live foods; live foods help bring out colour.23
Company who they like around
Keep in a shoal of at least 6 to 8. Good company includes other small rainbowfish, tetras, danios, small barbs, dwarf cichlids and Corydoras.21
The story where it all began
First collected in 1910 by W.C. van Heurn from a Mamberamo River tributary and described by Weber and de Beaufort in 1922. It entered the aquarium hobby around 1991-92 through collections by Charles Nishihira and Heiko Bleher.43
Fun facts for the dinner table
- 1
Males grow a notably deep, tall body while still tiny, at only about 3 to 3.5 cm long.1
- 2
It lives only in the Mamberamo system, one of New Guinea's longest rivers at over 2000 km.2
- 3
Newly hatched larvae can swim well straight away.4
- 4
Females can keep spawning for several days, scattering eggs among plants.3
- 5
Its wild streams are often only about 4 metres wide and half a metre deep, with slow flow over mud, gravel and leaf litter.4
Recognised by the official bits
- IUCN Red List
- Least Concern (assessed 6 December 2019)1
- Taxonomy
- Family Melanotaeniidae; described by Weber & de Beaufort in 1922, originally as Rhombatractus praecox3
The care rhythm Furry Diary remembers it for you
A typical home-care rhythm for a Dwarf Neon 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 Dwarf Neon Rainbowfish?
Feed small amounts once or twice a day. Furry Diary's starting plan is to feed daily small portions. Follow the food label and ask your vet for exact amounts.23 Furry Diary plan
What does a Dwarf Neon Rainbowfish eat, and what should it never eat?
It is an omnivore and accepts dried, frozen, and live foods; live foods help bring out its colour. Never feed it anything that is not designed for small tropical fish, and avoid overfeeding.23
How much space does a Dwarf Neon Rainbowfish need?
A minimum tank size of about 60 x 30 x 30 cm (around 54 litres) is recommended. This gives them open space for swimming near the upper water layers.2143
What temperature, light or water does a Dwarf Neon Rainbowfish need?
Keep the water temperature between 22-29°C, pH 6.6-8.0, and moderately hard water (about 5-15 dGH). Provide plenty of plants, including floating plants, and a lid on the tank as they can jump.2143
How often should I clean a Dwarf Neon Rainbowfish's home?
Furry Diary's starting plan suggests a weekly 25% water change, weekly water testing and glass cleaning, and a monthly filter rinse in old tank water. Regular cleaning helps keep them healthy.32 Furry Diary plan
Can a Dwarf Neon Rainbowfish live with others?
Yes, they are very peaceful and should be kept in a shoal of at least 6 to 8. Good tank mates include other small rainbowfish, tetras, danios, small barbs, dwarf cichlids, and Corydoras.21
How long does a Dwarf Neon Rainbowfish live?
Their lifespan varies depending on care and environment. For specific details, ask your vet or a good breeder.
Can I handle a Dwarf Neon Rainbowfish?
It is best not to handle them as they are delicate and can be stressed. They are lively swimmers that appreciate open space and should be observed in their tank.32
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.
Like 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.
- FishBase: Melanotaenia praecox summary fishbase.seused for origin, size, temperature, IUCN status, group size, body shape
- Seriously Fish: Melanotaenia praecox seriouslyfish.comused for care, tank size, water parameters, behaviour, diet
- Wikipedia: Melanotaenia praecox en.wikipedia.orgused for other names, colours, history, behaviour
- ANGFA Rainbowfishes: Melanotaenia praecox rainbowfish.angfaqld.org.auused for history, colours, size, water conditions
- 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.