Matano ricefish

Oryzias matanensis

Also known as Matanensis medaka

FreshwaterFish

Care at a glance

Temperature: 72–79°F (22–26°C)
pH: 7.5–8.5
Adult size: 2.2 in (5.5 cm)
Minimum tank: 20 gal (75 L)
Temperament: Peaceful
Social behavior: Schooling
Swim level: Middle
Difficulty: Medium
Breeding: Medium
Rarity: Rare
Origin: Lake Matano, Sulawesi
Family: Adrianichthyidae

Overview

The Matano ricefish is a peaceful, midwater schooler from a single ancient lake, and it makes a natural fish layer for a hard-water Sulawesi tank built around that lake's shrimp and snails. Keep it in a group of at least six so it shows its best behavior and color. It is community safe with other calm species that share its need for hard, alkaline water. Give it open water to cruise plus some cover at the edges. Feed small foods: fine flakes and micro pellets with frozen daphnia, cyclops, and brine shrimp. A tank of around 75 liters suits a shoal, matched to the same chemistry as Sulawesi shrimp.

In the wild

Oryzias matanensis is found only in Lake Matano, an ancient tectonic lake in the Malili system of central Sulawesi, along shorelines of hard, clear, mineral-rich water. Recreate that with a rocky, sandy layout, open swimming space, and stable hard, alkaline chemistry, roughly pH 7.5 to 8.5 and a warm 22 to 26 C. This is the same water that suits the lake's famous shrimp and snails, so it fits a Sulawesi biotope well.

Good to know

Oryzias matanensis is a ricefish of the family Adrianichthyidae, reaching about 5.5 centimeters, and it is endemic to a single lake, which is part of why it is listed as Vulnerable on the IUCN Red List. Like other medakas the female carries fertilized eggs at her vent before placing them on plants or rootwork, and it breeds at a medium level of difficulty in hard, alkaline water.

Did you know

Lake Matano is one of the oldest and deepest lakes on Earth, a tectonic basin plunging over 500 meters and counted in millions of years old. This little ricefish schools over some of the most ancient fresh water anywhere.