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Contents
Overview
Boeseman's rainbowfish (Melanotaenia boesemani) is one of the showiest freshwater fish around. Mature males are steel blue up front and blazing orange or yellow behind, with a tall back and edged fins; females are plainer, silvery with a golden sheen.
It comes from the Ayamaru Lakes on the Vogelkop Peninsula of western New Guinea (Indonesia), where wild populations are threatened, so the fish you buy should be captive-bred. It's a tireless schooling swimmer that cruises the middle of the tank and shows its best colors in the morning and when males display to each other. It's hardy and fine for a motivated beginner with a big tank, but keep in mind that store juveniles look gray: the color arrives with maturity.
Care and tank setup
This fish needs room to swim: plan on at least 55 gallons (200 L) and a 4-foot (120 cm) tank, with open water in front and dense planting along the sides and back. It prefers moderately hard to hard water with a neutral to alkaline pH; in soft, acidic water it fades and becomes more delicate.
- Keep a group of 6 or more, ideally with more females than males to spread out the courting.
- Use a filter with good circulation, change 25-30% of the water weekly and keep a lid on: they jump when startled.
- Some natural light or a gradual sunrise on your LED really brings out the males' colors.
It's peaceful, but its energy can stress slow or shy fish. Good tank mates include other rainbows, medium peaceful barbs, larger corydoras, loaches and small plecos. Dwarf shrimp may get eaten, especially the babies. The classic mistake is housing three of them in a 20-gallon tank.
Feeding
It's an easy omnivore. Use a quality pellet or flake with some spirulina as the staple and add frozen brine shrimp, daphnia, bloodworms or mysis a few times a week. It will also nibble blanched peas or zucchini. Two small feedings a day beat one big one; it feeds in midwater and at the surface rather than on the bottom.
Breeding
It's a continuous spawner: for days or weeks, a pair releases a few sticky eggs each morning among fine-leaved plants or into a yarn spawning mop. The parents don't guard them and will eat them, so move the mop to a separate container. Fry hatch in 7-10 days and need infusoria or liquid fry food, then baby brine shrimp. Crossed with other Melanotaenia it produces hybrids, so keep the species pure.
Compatible tank mates
Species from our database that share water parameters, size and temperament with the Boeseman's rainbowfish. Calculated from the data in each profile.
Bristlenose pleco Ancistrus sp. 26 gal (100 L) · 72–81 °F (22–27 °C) 
Betta fish Betta splendens 7 gal (25 L) · 75–82 °F (24–28 °C) 
Bronze cory Corydoras aeneus 21 gal (80 L) · 72–81 °F (22–27 °C) 
Guppy Poecilia reticulata 14 gal (54 L) · 72–82 °F (22–28 °C) 
Cherry barb Puntius titteya 16 gal (60 L) · 73–81 °F (23–27 °C) 
Nerite snail Neritina natalensis 5 gal (20 L) · 72–82 °F (22–28 °C) 
Horned nerite snail Clithon corona 5 gal (20 L) · 72–82 °F (22–28 °C) 
Dwarf gourami Trichogaster lalius 16 gal (60 L) · 75–82 °F (24–28 °C) 
Clown loach Chromobotia macracanthus 132 gal (500 L) · 77–86 °F (25–30 °C) 
Molly Poecilia sphenops 26 gal (100 L) · 75–82 °F (24–28 °C) 
Harlequin rasbora Trigonostigma heteromorpha 16 gal (60 L) · 72–81 °F (22–27 °C) 
Swordtail Xiphophorus hellerii 32 gal (120 L) · 72–81 °F (22–27 °C) Check the compatibility of your whole tank →
What not to keep it with
Popular species you shouldn’t house with the Boeseman's rainbowfish, and why.
- Common goldfish: incompatible temperatures
- Oranda goldfish: incompatible temperatures
- Oscar: one may eat the other due to size, incompatible temperaments
- Celestial pearl danio: incompatible temperatures, one may eat the other due to size
- Ember tetra: one may eat the other due to size
- Amano shrimp: eats shrimp
- Cherry shrimp: eats shrimp
Recommended equipment
What you need to keep the Boeseman's rainbowfish healthy, checked against Amazon stock.
Frequently asked questions
How many liters does a Boeseman's rainbowfish need?
At least about 200 liters for a group of at least 6 fish. More space always helps keep the water stable.
What water temperature does the Boeseman's rainbowfish need?
Between 25 and 29 °C, with a pH of 7 to 8.
What fish can live with the Boeseman's rainbowfish?
Based on water, size and temperament, it fits with species such as Bristlenose pleco, Betta fish, Bronze cory, Guppy and Cherry barb. Use our compatibility calculator to check your whole tank.
Can the Boeseman's rainbowfish be kept with shrimp?
Not recommended: because of its size or instinct, it will eat shrimp.
