[Ebook] Encyclopedia of Aquarium & Pond Fish – Directory of Freshwater Fish – Rainbowfish – Melanotoenia species

Directory of Freshwater Fish

Rainbowfish

Melanotoenia species

Boeseman’s Rainbowfish (Melanotaenia boesemani)

• ORIGINS: New Guinea, occurring in the Ajamaru Lakes area of the Vogelkop Peninsula.
• SIZE: 4 3⁄4 in (12 cm).
• DIET: Eats prepared diets and small live foods.
• WATER: Temperature 77–86°F (25–30°C); soft (50–100 mg/l) and acidic to alkaline (pH 6.5–8.0).
• TEMPERAMENT: Peaceful.

In terms of its coloration, Boeseman’s Rainbowfish is a fish of two halves. The head and front of the body are bluish, while the rear half is yellowish-orange, sometimes bordering on red. Males are brighter in color, display more elongated rays on their dorsal fins, and have a deeper body. Their aquarium needs to incorporate open areas for swimming as well as vegetation such as Java Moss (Vesicularia dubyana), which can serve as a spawning site. Females typically lay between 100 and 200 eggs, with hatching occurring approximately a week later. Originally collected by Dr. Marinus Boeseman on a Dutch expedition in 1954, this species was then rediscovered in 1982. Some live specimens were sent to Europe by Heiko Bleher, where they bred successfully, thus providing the foundation for today’s aquarium strains.

Dwarf Rainbowfish (Melanotaenia maccullochi)

• ORIGINS: Australia, in parts of Queensland and also in the Northern Territory.
• SIZE: 2 3⁄4 in (7 cm).
• DIET: Eats both prepared diets and small live foods.
• WATER: Temperature 72–86°F (22–30°C); soft (50–100 mg/l) and acidic to alkaline (pH 5.5–7.5).
• TEMPERAMENT: Peaceful.

Dark horizontal stripes along the sides of the body characterize this rainbowfish; the stripes become more wavy and broken on the lower parts. Females are less colorful but grow larger than males. There are color differences between isolated populations; the orange fin markings that typify fish around Cairns are absent in those from the Jardine River region. Dwarf Rainbowfish occurring near the Litchfield National Park in the Northern Territory have more yellowish bodies and are decidedly smaller in size.

Parkinsoni Rainbowfish (Melanotaenia parkinsoni)

• ORIGINS: Eastern New Guinea, between Milne Bay and the Kemp Welsh River.
• SIZE: 5 1⁄2 in (14 cm).
• DIET: Eats both prepared diets and small live foods.
• WATER: Temperature 77–84°F (25–29°C); hard (100–150 mg/l) and alkaline (pH 7.6).
• TEMPERAMENT: Peaceful.

The attractive appearance of this rainbowfish is best appreciated under subdued lighting, which emphasizes the yellow, golden, and blue areas on the body and fins. Individuals display some variation in coloration—some are more orange than yellow. Females resemble males but are generally duller in color. Some males have enlarged anal and dorsal fins, and the fins in some individuals have a slightly ragged appearance.

Lake Kutubu Rainbowfish (Melanotaenia lacustris)

• ORIGINS: Central New Guinea, in Lake Kutubu and the Soro River, which flows out from the lake.
• SIZE: 4 3⁄4 in (12 cm).
• DIET: Eats both prepared diets and small live foods.
• WATER: Temperature 72–77°F (22–25°C); hard (100–150 mg/l) and alkaline (pH 8.0–9.0).
• TEMPERAMENT: Peaceful.

The blue coloration of these rainbowfish varies according to water conditions and diet. An orange area on the nape of the neck indicates that they are in spawning condition. Spawning itself can be a protracted affair, with the females laying eggs in batches over the course of several days. In the wild, these fish are found in parts of Lake Kutubu where there is floating vegetation near the surface. In aquariums, they should be kept in single-species groups to avoid hybridization with other fish.

Lake Tebera Rainbowfish (Melanotaenia herbertaxelrod)

• ORIGINS: Central highlands of New Guinea near Lake Tebera, part of the Purari River system.
• SIZE: 5 in (13 cm).
• DIET: Eats both prepared diets and small live foods.
• WATER: Temperature 75–81°F (24–27°C); hard (100–150 mg/l) and alkaline (pH 7.5).
• TEMPERAMENT: Peaceful.

The yellowish body of these fish has a dark central band along the midline. The middle section of the first part of the dorsal fin is longer in male Lake Teberas. The males’ appearance alters at the start of the spawning period, when they develop a blue or white stripe that runs from the dorsal fin and down over the head. This stripe gradually becomes much darker in color. Lake Teberas live in shallow, vegetated areas, so they will benefit from having a well-planted area in their tank. Females lay up to 150 eggs, which hatch about 10 days later.

New Guinea Rainbowfish (Melanotaenia affinis)

• ORIGINS: Northern New Guinea, including the Sepik River (Pagwi), and Madang (Blue Water Creek morph).
• SIZE: 5 1⁄2 in (14 cm).
• DIET: Eats both prepared diets and small live foods.
• WATER: Temperature 70–82°F (21–28°C); hard (100–150 mg/l) and neutral (pH 7.0).
• TEMPERAMENT: Peaceful.

Three separate varieties of this species are known, with the so-called Standard having the widest range. In all cases, males are more colorful, with elaborate dorsal and anal fins, and grow slightly larger than females. New Guinea Rainbowfish have proved to be very adaptable, reflecting the fact that in the wild their environment can change markedly though the year. Like related species, they should be kept in shoals. Females lay up to 200 eggs when spawning.

Splendid Rainbowfish (Melanotaenia splendida)

• ORIGINS: Northern Australia, Aru Island, and between Etus Bay and the Aramia River in southern New Guinea.
• SIZE: 6 in (15 cm).
• DIET: Eats both prepared diets and small live foods.
• WATER: Temperature 72–82°F (22–28°C); soft (50–100 mg/l) and acidic to alkaline (pH 5.6–7.4).
• TEMPERAMENT: Peaceful.

There are between four and six subspecies of this rainbowfish, all of which show reddish-brown speckling on the body. Males are generally more brightly colored and have deeper bodies than the females. The young of both sexes are duller than the adults, taking up to a year to acquire their full coloration. It is vital to keep the nitrate level in the tank low, so make sure the filtration system is efficient and carry out partial water changes every week or so.

Peacock Rainbowfish (Melanotaenia praecox)

• ORIGINS: New Guinea, occurring in small areas of the Mamberamo River system, near Iritoi, Dabra, and Siewa.
• SIZE: 2 1⁄2 in (6 cm).
• DIET: Eats both prepared diets and small live foods.
• WATER: Temperature 75–81°F (24–27°C); soft (50–100 mg/l) and acidic (pH 6.5).
• TEMPERAMENT: Peaceful.

The brilliant neon blue of these rainbowfish is displayed to best effect when they are kept in aquariums with floating plants to diffuse the light. Well-oxygenated water is also important, since Peacock Rainbowfish naturally inhabit fast-flowing waters. It has been suggested that only males display red edges to their fins, although this characteristic can in fact be seen in both sexes. Yellow-fin edges are more common in aquarium strains. One recently discovered wild population has red stripes on the body. Females spawn over several days, producing up to 50 eggs per day; the eggs stick to vegetation. Hatching takes about a week, and the fry can be reared on brine shrimp. Feeding the adults well makes them less likely to eat their eggs or offspring.