Red Rainbowfish

Geographic Origin and Biotope: Endemic only to Lake Sentani in New Guinea (Papua). Lives near the turbid shores of this specific mountain lake, where the waters are hard, alkaline and rich in submerged lacustrine vegetation.

Taxonomy and Morphology: Red Rainbowfish. Corpulent and very high species (lozenge shape). It is the most famous and impressive of the Melanotaeniidae family. It can easily exceed 15 cm (6 inches) in length and 6 cm (2.5 inches) in back height as an adult.

Social Behavior: Extremely gregarious and very lively swimmer. Absolutely must be kept in schools of at least 6-8 specimens with a proportion of more females for each male. Males engage in wonderful color parade exhibitions to establish hierarchies and fascinate females.

Coloration and Sexual Dimorphism: Dramatic sexual dimorphism. Adult males, if well fed, ignite with an incomparable metallic fire red or burgundy color, with small bright silver scales on the body. Females are slender and an anonymous transparent yellow/olive for life.

Aquarium Setup: Tank at least 120-150 cm (4-5 feet) long (minimum 250 liters / 65 gallons) given the lightning-fast swimming. There must be wide open central swimming spaces with lateral thickets of Vallisneria or Cryptocoryne. Does not like excessive light: shade with floating plants (Ceratopteris).

Diet and Feeding: Extremely voracious omnivore that feeds in the upper part of the water column. Flake food and small sinking pellets enriched with astaxanthin (to enhance the red) are the base; frozen bloodworms, daphnia and brine shrimp nauplii are essential to unleash the iridescence.

Water Quality: HARD and alkaline water species: unlike common South American fish, G. incisus suffers and wastes away in soft or acidic waters. Maintain pH at 7.5-8.0 and a GH between 10 and 20. The temperature must be cool, around 23-25°C (73-77°F). Frequent partial water changes.

Compatibility and Tankmates: Perfect for community tanks of robust and good-sized fish. Splendid companion for other Rainbowfish species (Melanotaenia praecox or boesemani), large Corydoras, Ancistrus. Never pair with small fish (Microrasboras) or shy soft-water fish (Discus).

Aquarium Reproduction: They scatter adhesive eggs among the bushes of fine plants (mosses or spawning mops) every morning for weeks. The breeders must be removed or they will devour the clutch. The fry are extremely fragile and tiny, requiring infusoria and rotifers for the first few days.

Risks and Diseases: Old males develop an incredibly curved and stocky back (physiological gibbosity). They are vulnerable to Fish Tuberculosis (Mycobacteriosis) if kept in overcrowded, hot (over 28°C / 82°F) and nitrate-polluted waters.