Oryzias Javanicus

Datasheet

General Description

The Javanese Ricefish, scientifically known as Oryzias Javanicus, is a small species with a body size ranging up to 3.5cm. It is distinct due to its truncate caudal fin, setting it apart from other Oryzias species like O. bonneorum and O. nebulosus. Belonging to the Beloniformes order, this fish is often referred to as the "blue-eyed ricefish" and is part of the Adrianichthyidae family.

Aquarium Setup

When setting up an aquarium for the Javanese Ricefish, a minimum tank size of 40 litres is recommended (see table). The species does not have specific décor requirements but tends to showcase its best colors in a habitat resembling its natural environment. Such setups may include a sandy substrate, water-worn tree roots, branches, and leaf litter. Live plants are suitable, though not all aquatic species thrive in brackish conditions. Maintaining a salinity range by adding marine salt, preferably in a ratio of 1-3 g/L, can benefit the fish, ensuring its well-being.

Behaviour

Known to be generally peaceful, the Javanese Ricefish may not always be the ideal addition to all community tanks due to its small size. It usually thrives when kept with diminutive species sharing similar conditions. The fish tends to be non-aggressive towards its own kind, preferring groups of 8 or more. However, male ricefish can be competitive during courtship.

Feeding and Diet

As micropredators, Javanese Ricefish feed on small insects, worms, crustaceans, and zooplankton in their natural habitat. In an aquarium, they readily accept a diet of small live and frozen foods like Daphnia, Artemia, and bloodworms. Additionally, offering high-quality flakes and granules suitable for their size on a daily basis is recommended for their overall health.

Reproduction & Dimorphism

Breeding Javanese Ricefish proves to be relatively easy and prolific, with females capable of laying eggs frequently. During spawning, males darken in color, defend territories, and try to attract females. Females produce adhesive eggs that are fertilized externally and can be left hanging from the female before being deposited among vegetation. The incubation period is typically 1-3 weeks, with fry being able to accept small live food upon hatching. Mature males exhibit yellow bands on their caudal fins and possess elongated rays in their dorsal and anal fins, differing from females.

Habitat and Distribution

These ricefish species are commonly found in brackish coastal streams and pools, including mangrove swamps and forests. They also inhabit freshwater habitats and exhibit tolerance towards a wide salinity range. The Javanese Ricefish has a wide distribution range, spanning Peninsular Thailand, Malaysia, Singapore, and multiple Indonesian islands such as Sumatra, Java, Borneo, Bali, and Sulawesi. The species was originally described in Indonesia at the Panimbang River in Perdana.