Boeseman’s Rainbowfish

Boeseman’s Rainbowfish Melanotaenia boesemani

Type of Animal:

Lakes/lake tributaries/lake shallows/streams/rivers/ponds/estuarine areas w/ dense vegetation, densely vegetated swampy shallow areas, need pH of 6-9 (slightly acidic to alkaline)

Ayamaru Lakes & nearby tributaries/lakes in West Papua

Long deep shape w/ arched back/narrow head, small fins, large eyes, back half of fish more colorful than front half, back half often fiery red w/ orange/yellow highlights, front half different shades of blue/purple/green, halves meet in middle w/ green/blackish vertical stripes, females similar color to males but coloration much less intense, females also have silver on them, breeding males have bluish-purplish heads, males deeper bodied than females

Algae, daphnia, crustaceans, insects, insect larvae, tubifex worms, bloodworms, microworms, vinegar eels, plant matter, younger members of own species

Status in Wild:

Breeding in aquariums, zoos, & aquaculture. Captive breeding reducing demand for wild-caught fish. Restrictions on trade of wild-caught fish.

Schools of 5-30 fish w/ more females than males

Additional Info:

Young: Fry
Group: School

1-2 weeks

Life Span:
5-8 years

Body Length:
Male: 4-4.5 in
Female: 3-4 in

Tail Width:
Male: 1 in
Female: 0.5 in

Main predators of adults are freshwater snappers, grunters, & waterfowl. Adult rainbowfish prey on fry/small juveniles.
Endangered due to overcollection, water pollution, habitat degradation, introduction of invasive species, overfishing, & small range.
Also called Boesemani Rainbowfish & Bicolor Rainbowfish.
Color intensity can be sign of mood/health.
Like other rainbowfish, they’re very active swimmers.
Dorsal/ventral fins lend stability in swimming while tail/caudal fin helps it propel through water. Pectoral fins for locomotion & side to side movement.
Spawning lasts a few weeks w/ female laying new fertilized eggs each day.
Fry tend to stay near water surface.
Males often show better coloration in presence of females/other males & male competition often results in better breeding.
Females scatter 10-20 eggs on vegetation.
After female produces eggs, male displays colors & directs her to spawning site.

Fun Fact(s):
In the 1980s, these fish were exported in tens of thousands, often in single month. They were almost unknown in aquarium trade before 1980s.
Named for Dutch ichthyologist Marinus Boeseman.
These fish said to have formic taste to them due to some of their diet.
While common in aquarium trade, they’re endangered in wild. Prized for their colors. Fortunately, many are captive bred reducing demand for wild-caught fish.

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