TankBud

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
Egg layer · Medium
Rarity
Rare
Family
Adrianichthyidae
Origin
Mekong basin pools

Overview

The Mekong ricefish is a small, peaceful medaka for a quiet planted tank, best shown as a shoal. It is a good choice once you have kept a few easier fish.

Did you know

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

Caring for the Mekong ricefish

Give Mekong ricefish a well planted, quietly filtered tank of at least 11 gal (40 L). Calm water, fine plants and an open surface suit them. Keep the current low so they can hold in the midwater and feed near the surface.

They like warm, soft to neutral water at 72 to 79°F (22 to 26°C) and a pH of 6.0 to 7.5. Feed small foods such as crushed flake, frozen cyclops and daphnia, microworm and baby brine shrimp.

Keep at least six together, and a larger group is better still. They are community safe with other tiny, gentle fish, but keep nothing big enough to treat them as food.

Displaying males carry orange-red edges on the tail and fins. As with other medakas, the female totes her egg cluster at the vent before combing it off onto plants. Breeding is a moderate challenge, and a settled, well planted tank keeps a colony breeding quietly.

Good to know

Oryzias mekongensis is a ricefish of the family Adrianichthyidae, sold under the trade name Mekong redfin.

In the wild

Oryzias mekongensis lives in the Mekong basin, mostly in still and slow floodplain waters. These include pools, ditches and marshy margins among plants.

Weekly picks

Tank mates

The Mekong ricefish is a peaceful, schooling species that keeps to the middle. These picks share a community profile with it, are safe together in both directions, and overlap on water type, temperature and pH.

Check the full mix in the stocking calculator

Common questions

What size tank does a Mekong ricefish need?

A Mekong ricefish needs at least 11 gal (40 L). It spends most of its time in the middle.

What temperature and pH does a Mekong ricefish need?

A Mekong ricefish is comfortable at 72–79°F (22–26°C) with a pH of 6.0–7.5.

What does a Mekong ricefish eat?

A Mekong ricefish eats small foods, such as crushed flake and microworm. Frozen cyclops, daphnia and baby brine shrimp suit it too.

How big does a Mekong ricefish get?

An adult Mekong ricefish reaches about 1.2 in (3 cm).

Does a Mekong ricefish need a group?

Yes. A Mekong ricefish is a schooling species and should be kept in a group, not singly.

How can you tell a male Mekong ricefish from a female?

Males carry orange-red edges on the tail and fins when they display.

How does a Mekong ricefish breed?

A Mekong ricefish female totes her egg cluster at the vent, then combs it off onto plants. Breeding is a moderate challenge, best tried in a settled, well planted tank.

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