New Guinea rainbowfish - Melanotaenia affinis

Scientific name: Melanotaenia affinis

Common name: New Guinea rainbowfish

Family: Melanotaeniidae

Usual size in fish tanks: 10 - 13 cm (3.94 - 5.12 inch)

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Recommended pH range for the species: 6.1 - 7.2

Recommended water hardness (dGH): 3 - 16°N (53.57 - 285.71ppm)

0°C 32°F30°C 86°F

Recommended temperature: 21 - 27 °C (69.8 - 80.6°F)

The way how these fish reproduce: Spawning

Where the species comes from: Oceania

Temperament to its own species: peaceful

Temperament toward other fish species: peaceful

Usual place in the tank: Top levels

Food and Feeding

Like most rainbowfish, the New Guinea Rainbowfish (Melanotaenia affinis) is an enthusiastic eater and will readily accept a variety of foods. A high-quality flake food should serve as the staple diet, but it is essential to supplement it with live or frozen treats such as bloodworms, brine shrimp, and daphnia to enhance their coloration and overall health. Additionally, they enjoy nibbling on blanched lettuce and spinach, adding some plant matter to their diet.

Origin and Natural Habitat

Native to Oceania, Melanotaenia affinis is found in the freshwater rivers, streams, and lakes of Australia and New Guinea. These environments are often densely planted and feature moderate water currents, providing them with ample space to swim and forage.

Sexing

Determining the sex of Melanotaenia affinis is relatively straightforward. Males display more vibrant coloration and have extended dorsal and anal fins compared to the more subdued and rounded appearance of females.

Breeding

To encourage breeding, introduce fine-leaved plants such as Java Moss or provide spawning mops as egg-laying sites. The eggs are adhesive and will attach to the plants or mops, with females laying a few eggs each day over several days. Once spawning is complete, it is best to remove the parents to prevent predation. The eggs typically hatch within a week, and once the fry become free-swimming, they should be fed infusoria or newly hatched brine shrimp to support their early development.

Lifespan

With proper care, Melanotaenia affinis can live for 5 to 8 years. Maintaining high water quality and providing a well-balanced diet are key factors in ensuring a long and healthy life.

Tank Requirements and Behavior

As a shoaling species, Melanotaenia affinis thrives in groups of at least six individuals. They are active swimmers and require an aquarium setup that includes both open swimming spaces and planted areas. A well-maintained tank with regular water changes will keep them in optimal health. Given their peaceful nature, they are excellent additions to community tanks with other non-aggressive species.

Suitable Tankmates

The New Guinea Rainbowfish is a great choice for a community aquarium due to its peaceful temperament. Compatible tankmates include:

Neon Tetras (Paracheirodon innesi)
Harlequin Rasboras (Trigonostigma heteromorpha)
Corydoras Catfish (Corydoras spp.)
Pearl Gouramis (Trichopodus leerii)
Zebra Danios (Danio rerio)
Guppies (Poecilia reticulata)

Suitable Plants

Live plants help mimic the natural habitat of Melanotaenia affinis and contribute to water quality. Some excellent choices for a planted aquarium include:

Anubias (Anubias spp.)
Java Fern (Microsorum pteropus)
Amazon Sword (Echinodorus amazonicus)
Hornwort (Ceratophyllum demersum)
Water Wisteria (Hygrophila difformis)
Cryptocoryne (Cryptocoryne spp.)

Short Description

The New Guinea Rainbowfish (Melanotaenia affinis) is a stunning and peaceful species that thrives in well-maintained aquariums with open swimming areas and live plants. Due to their shoaling nature, they should be kept in groups to display their best colors and behavior. They adapt well to a variety of water parameters, but regular water changes are necessary to keep them healthy. Their active and social nature makes them an excellent choice for community tanks.