Mekong ricefish

Oryzias mekongensis

Also known as Redfin ricefish, Red ricefish

FreshwaterFish

Mekong ricefish (Oryzias mekongensis) — Andrewbogott · CC BY-SA 4.0

Care at a glance

Temperature: 72–79°F (22–26°C)
pH: 6.0–7.5
Adult size: 1.2 in (3 cm)
Minimum tank: 11 gal (40 L)
Temperament: Peaceful
Social behavior: Schooling
Swim level: Middle
Difficulty: Medium
Breeding: Medium
Rarity: Rare
Origin: Mekong basin pools
Family: Adrianichthyidae

Overview

The Mekong ricefish is a small, peaceful medaka for a quiet planted tank, best shown as a shoal where the males flare their red-edged fins at one another. Keep at least six together, and a larger group is better still. It is community safe with other tiny, gentle fish, but keep nothing big enough to treat it as food. Give it calm water, fine plants, and an open surface. Feed small foods such as crushed flake, frozen cyclops and daphnia, microworm, and baby brine shrimp. A gently filtered tank of around 40 liters with plenty of planting keeps a colony breeding quietly.

In the wild

Oryzias mekongensis lives in the Mekong basin, mostly in still and slow floodplain waters such as pools, ditches, and marshy margins among plants. Recreate that with a well planted, quietly filtered tank and soft, gentle water. It likes warm, soft to neutral conditions, about 22 to 26 C at roughly pH 6.0 to 7.5, with little current so it can hold in the midwater and feed near the surface.

Good to know

Oryzias mekongensis is a ricefish of the family Adrianichthyidae, reaching only about 3 centimeters, and displaying males carry orange-red edges on the tail and fins that give it the trade name Mekong redfin. As with other medakas the female totes her egg cluster at the vent before combing it off onto plants, and it breeds at a medium level in a settled planted tank.

Did you know

Out of a shoal these fish look almost colorless. The red only comes up when the males display to each other, so a lone specimen in a shop tank rarely shows why it is called the redfin ricefish.