Mekong ricefish

Oryzias mekongensis

A slender translucent ricefish with orange-red upper and lower tail edges.

A miniature freshwater ricefish from the Mekong basin. Narrow orange-red tail margins stand out against its subtle body colour. Paler females are the same species.

Adult length: Up to 2.1 cm (standard length, without the tail fin)
Water temperature: 23–27 °C
pH: 6–7.5
Hardness: 2–15 dGH

Native range: Asia: Mekong basin.

Natural habitat: Inhabits permanent shallow standing water in ditches, canals and ponds, usually among dense, fine-leaved submerged plants.

Tiny food, gentle flow and mild companions matter. Avoid large predators and vigorous food competitors. Small adult size does not justify arbitrary miniature containers.

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Appearance and identification

Tail pigmentation helps compare it with O. minutillus, but O. songkhramensis also has red tail markings. Check head shape, pigmentation, male anal-fin structures and locality; a red tail alone is not enough.

Same-species behaviour

Keep eight or more.

Space requirements

A 40 × 20 cm base. Use stable mature water, fine cover and open swimming space.

Diet and feeding

Offer finely powdered foods, microworms and newly hatched Artemia. Check that particles are actually swallowed, not just chased.

Compatibility limits

Avoid large fish, predators and strong food competitors. Keep different miniature ricefish apart.

Aquarium environment

Fine vegetation supplies refuge and egg-attachment surfaces. Females carry eggs briefly before attaching them to structures; adults may eat fry.

Sources