Javanese ricefish

Care at a glance

Overview

Keep a group of at least six in a tank of around 40 liters, since these are small, social surface-feeders. They sit in the upper water and pick at small foods, so offer fine flake, micro-pellets, and small live or frozen items like daphnia and baby brine shrimp. Gentle filtration and floating or fine-leaved plants suit them. Only house them with other tiny, peaceful fish, since anything bigger will outcompete or eat them.

In the wild

The Javanese ricefish lives in shallow, slow water across Thailand and the Sunda Islands, from rice paddies and ditches to estuaries, and tolerates fresh through slightly brackish conditions. These spots are warm, planted, and soft-bottomed. A small planted tank with gentle flow suits it, with a pH from 6 to 7.5 and temps in the mid to upper 20s C. A touch of salt is optional, not required.

Good to know

Oryzias javanicus is in the family Adrianichthyidae, the ricefishes and medakas, and stays tiny at about 3.5 cm. The body is near-transparent with a faint silvery or yellow cast. It is an egg layer with a distinctive habit: the female carries a cluster of eggs near her vent for a while before attaching them to plants. Habitat loss is the main pressure, though it isn't formally listed as threatened.

Did you know

The female doesn't lay and leave. She swims around with a bunch of fertilized eggs trailing from her belly, then brushes them off onto plants once they are ready, which is fun to watch in a quiet tank.

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