At a glance the quick version
FishBase gives 9 cm standard length for males (7 cm females); Seriously Fish 110 mm; ANGFA up to 12 cm, usually under 10 cm.
Looks how to spot one
Scales, deep-bodied rainbowfish
A deep-bodied, laterally flattened rainbowfish. Adult males develop a tall back and a striking two-tone pattern. Young fish start out plain and colour up over a year or more.243
Personality what they are like
Peaceful and a little skittish, gaining confidence in a larger shoal. Its quick movements can unsettle very small or slow tankmates.2
Daily activity how busy a day looks
An active midwater swimmer that needs open swimming space as well as planted areas.2
Grooming and care the hands-on bits
Regular water changes and a varied diet support good colour. A covered tank is sensible for active rainbowfish.24
Home where they are happiest
Minimum about 120 x 30 x 30 cm (around 108 litres); FishBase suggests at least 80 cm length. Temperature 27-30 C (ANGFA notes 26-27 C in the wild), pH 7.0-8.0, moderately hard water (about 10-20 dGH). Dense planting plus open swimming room.214
Food basics what goes in the bowl
Omnivore that accepts most dried, frozen and live foods; meatier foods such as bloodworm and brine shrimp help colour.23
Company who they like around
Keep in a shoal of at least 6 to 8 (FishBase says 5 or more), with as many or more females than males. Good companions include other rainbowfish, barbs, danios, tetras and catfish.213
The story where it all began
First collected by Sten Bergman in 1948-49 and again by Marinus Boeseman in 1955, it was formally described by Gerald Allen and Norbert Cross in 1980 and named after Boeseman. Live fish reached the aquarium hobby in 1982, and today almost all aquarium fish are farm-bred.432
Fun facts for the dinner table
- 1
It is named after the Dutch ichthyologist Marinus Boeseman, who collected early specimens.3
- 2
Its colours can shift with mood and often look strongest at certain times of day.3
- 3
Juveniles are quite plain and may take more than a year to show full adult colour.2
- 4
Its whole wild range is a small cluster of lakes on one peninsula of New Guinea.1
Recognised by the official bits
- IUCN Red List
- Endangered (assessed 4 December 2019)1
- Taxonomy
- Family Melanotaeniidae; described by Allen & Cross in 19801
The care rhythm Furry Diary remembers it for you
A typical home-care rhythm for a Boeseman's 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
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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 [email protected] and we will fix it.
- FishBase: Melanotaenia boesemani summary fishbase.seused for origin, size, water parameters, IUCN status, group size
- Seriously Fish: Melanotaenia boesemani seriouslyfish.comused for care, tank size, diet, behaviour, development
- Wikipedia: Melanotaenia boesemani en.wikipedia.orgused for colours, lifespan, naming, companions
- ANGFA Rainbowfishes: Melanotaenia boesemani rainbowfish.angfaqld.org.auused for history, colours, size, wild water conditions
Checked 2026-09-30. Text is written in our own words from these sources.