Madagascar Rainbowfish

Geographic Origin and Biotope: Endemic to eastern Madagascar's vanishing coastal rainforest rivers. Moderate-to-strong current streams with pebble and sand beds. 90% of natural habitat destroyed in recent decades.

Taxonomy and Morphology: Endemic Bedotiidae family, reaching 10-12 cm. Elongated with two well-separated dorsal fins (convergent evolution with Melanotaeniidae). Large forked caudal for efficient current swimming.

Social Behavior: Active schooler with constant male display competitions. Needs groups of 6-8+ to distribute hierarchical pressure.

Coloration and Sexual Dimorphism: Olive-gold body with iridescent dark lateral stripe. Male fins conspicuously edged in intense black with yellow-orange or red margins — the diagnostic feature. Females have transparent fins.

Tank Setup: 150+ liters (100+ cm) with strong current from powerheads. Pebble and fine gravel. Robust current-resistant plants. Lid mandatory: jumps frequently.

Feeding: Opportunistic omnivore. Easily accepts flakes, pellets, frozen foods. Varied diet intensifies male fin borders.

Water Quality: Neutral (pH 6.5-7.5), moderately hard (GH 8-18), 20-25°C — cooler than average tropical. Oxygenation is critical: stagnant water causes rapid gill infections. 25-30% weekly water changes.

Compatibility: Excellent with robust schooling fish: Danios, White Clouds, peaceful Barbs. Compatible with small African cichlids.

Reproduction: Egg scatterer among plants. Large adhesive eggs on mosses. 6-10 day incubation. No parental care.

Risks: Mycobacteriosis (fish tuberculosis) is documented: progressive wasting, spinal deformities, skin lesions. No effective treatment. Ex-situ conservation (aquarium keeping) is critical for species survival.