Celebes Medaka

Oryzias celebensis is a ricefish endemic to the island of Sulawesi, Indonesia, where it inhabits warm, hard, alkaline lake systems and streams. Males display a distinctive silvery-blue body sheen with yellow to orange fin margins, making them one of the more colourful species in the Oryzias genus. They are schooling fish that look most impressive in groups of ten or more.

Unlike the common Japanese medaka, O. celebensis requires warm, hard, alkaline water to thrive — conditions typical of the ancient lake systems of Sulawesi. Standard planted tank water parameters may be too soft and acidic for long-term health. Crushed coral or aragonite substrate can help maintain the appropriate hardness and pH.

Breeding follows the standard Oryzias pattern: females carry fertilised egg clusters attached to their bodies before depositing them on fine-leaved plants or spawning mops. The eggs develop over 10–14 days at warm temperatures. Fry are free-swimming from hatching and accept micro foods immediately.

Water: 25-30°C, pH 7.0-8.5, hard (GH 10-20) — warm, alkaline conditions essential for long-term health. Tank: 30 L minimum for a school; fine-leaved plants or spawning mops; moderate to strong lighting. Feeding: micro pellets, baby brine shrimp, daphnia, and crushed flake — easy to feed. Breeding: egg scatterer; females carry eggs briefly before depositing on plants; fry accept microfood immediately. Compatibility: peaceful schooling fish; excellent with other Sulawesi species (Snails, shrimp) in species biotope.