Celebes Rainbowfish

Geographic Origin and Biotope: Endemic to Sulawesi (formerly Celebes), Indonesia. Inhabits moderate-current rivers draining into the Gulf of Maros. Crystal-clear, hard, slightly alkaline water from karstic limestone substrates. Habitat severely threatened.

Taxonomy and Morphology: Endemic Telmatherinidae (max 7-8 cm). Elongated, transparent body. Two dorsal fins; the second dorsal and anal fins bear elegant long black filamentous extensions in males. Large iridescent blue eyes.

Social Behavior: Active peaceful schooler. Males display constantly with erect fins and extended filaments. Groups of 6-8+ needed.

Coloration and Sexual Dimorphism: Transparent amber-gold body with iridescent yellow-green lateral band. Males develop black fin filaments and overall yellow intensification. Females smaller and transparent.

Tank Setup: 80-100+ liters with moderate current. Fine-leaved plants and floating cover. Light-colored fine sand. Mandatory lid.

Feeding: Surface/mid-water micro-predator. Accepts fine flakes, artemia nauplii, daphnia, cyclops. Small mouth: oversized granules are ignored.

Water Quality: WARNING: requires HARD, ALKALINE water (pH 7.0-8.0, GH 10-20). Soft acidic water weakens it osmotically. European hard tap water is often perfect.

Compatibility: With other hard-water fish: Pseudomugil, Oryzias, Melanotaenia praecox, Caridina/Neocaridina shrimp. Avoid fin-nippers.

Reproduction: Daily egg scatterer. Filamentous adhesive eggs in mosses. 10-14 day incubation. Parents eat eggs. Fry need infusoria first week.

Risks: Osmotic shock in soft water. Fin filaments are fragile and don't fully regrow once torn. Columnaris attacks damaged filaments.