Boesemani rainbowfish / Boeseman's rainbow (Melanotaenia boesemani) care guide

Quick facts

Adult size: 10 cm
Lifespan: can live up to 8 years
Tank zone: mid-top
Temperament: peaceful
Difficulty: beginner
Schooling: recommended 6+ (critical minimum 4, thrives at 10+)

Water parameters

Temperature: 24–28°C
pH: 7.0 to 8.0
Hardness: 10 to 20 dGH

Tank requirements

Minimum volume: 200 L
Minimum length: 100 cm
Flow: moderate
Lighting: any
Substrate: any
Open swimming room: needed
Lid: required - jumper

Feeding

Diet: omnivore, feeds primarily at the mid-top.

Easy feeder. Quality flake, small pellets, frozen daphnia and brine shrimp. Color intensifies with varied diet and good water quality.

Compatibility

The most popular rainbowfish in the hobby. Males develop spectacular blue-rear/orange-front coloration at maturity; juveniles are dull silver and don't look anything like the adult fish on the label
Peaceful but active; fast enough to startle slow feeders like discus or angelfish. Best with similar-paced mid-water fish
Prefers hard alkaline water, which makes them unusual among tropical community fish. Good companions for Malawi cichlids in larger tanks, or with livebearers and other hard-water species
Males display constantly to each other; the more males, the better the color. A group of all males is fine
Jumpers. Cover the tank or lose fish. This is the #1 cause of rainbowfish death in new setups

Habitat

Endemic to Lake Ayamaru and surrounding lakes in the Vogelkop peninsula (Bird's Head) of West Papua, Indonesia. Found in clear, hard, alkaline water (pH 7.5-8.5) over rocky and vegetated substrates. Wild populations are IUCN Endangered from habitat degradation; virtually all aquarium stock is captive-bred.

Breeding

Egg scatterer that deposits eggs among fine-leaved plants or spawning mops over a period of days. Unlike many fish, rainbowfish spawn a few eggs each morning rather than in one big event. Eggs hatch in 7-10 days. Fry are tiny and need infusoria for the first few days. Males display intensely at dawn, which is when most spawning occurs. Separate the eggs from the adults or they'll be eaten.

Common problems

Washed-out color in stressed or recently purchased fish. Boesemanis can look pale gray in a store tank and take weeks to color up in good conditions. Males need to compete with other males to show their best color; a solo male in a community tank never looks as good as one in a group. Mycobacterium (fish TB) affects rainbowfish more than many species; fish that slowly waste away despite eating may have this incurable bacterial infection. Quarantine new additions.

Bioload

Bioload coefficient: 3.0 (moderate for a 10 cm schooling fish; less waste than similarly-sized barbs).

Bioload coefficients are calibrated against the neon tetra as the anchor (1.0). See the methodology page for the formula and how each value was derived.