Oryzias eversi

Adult Oryzias eversi reach about 4 cm in length. They resemble other members of the genus Oryzias. Males have more intense body colour, and their dorsal and anal fins are larger with elongated rays. Females have a silvery tone and much smaller fins. Otherwise they share the typical features of all ricefish.

This species is naturally found in Southeast Asia, where it is endemic to the Indonesian island of Sulawesi, occurring only in its southern regions. Oryzias eversi inhabits small rivers and streams flowing through tropical forests. The water in these habitats is clear and clean, with stable and relatively low temperatures year-round. The aquatic vegetation consists mainly of algae attached to rocky surfaces.

This is a peaceful schooling fish. Oryzias eversi should be kept in a group with others of its kind, but should not be housed with other related Oryzias species to avoid hybridisation. It gets along well with other calm fish of similar size.

Due to its small size, a school of Oryzias eversi is comfortable in a tank of at least 60 litres. Tank décor is not critical and can be chosen to your preference. However, the fish looks most natural in a setup mimicking its natural habitat. Use sandy substrate with rocks, a few pieces of wood, and live plants. Adding dried leaves such as almond or oak leaves adds to the natural feel. Maintaining high water quality is essential for this species. Because these fish live in flowing streams, they are very sensitive to the buildup of organic waste. The tank must be equipped with a powerful filtration system. Weekly water changes of 20–30% and regular cleaning are also necessary. Overall, care for this species is comparable to that of other fish.

This species is not fussy about food and readily accepts various appropriately sized foods, whether dry, frozen, or live. For good health, offer a varied diet combining, for example, flakes or pellets with small bloodworms or brine shrimp.

Breeding is straightforward: simply keep males and females together. A distinctive feature of Oryzias eversi, like all ricefish, is its unusual method of carrying eggs. The female lays 20–30 eggs that she carries attached by thin filaments like a bunch beneath her anal fin. The incubation period lasts about 18–19 days. During this time the female seeks shelter among dense plants to protect the eggs. After the fry hatch, parental instinct weakens and adults may eat their young. To improve survival, transfer the fry to a separate tank.

These fish are hardy and undemanding. Disease usually appears only when conditions deteriorate significantly. In a balanced aquarium ecosystem, health problems are typically absent.

When selecting Oryzias eversi, choose active individuals that school together and show no visible damage to fins or skin. Make sure the fish show natural curiosity and do not appear emaciated, as this species is sensitive to water quality and transport stress. In the shop, check that the tank is clean and there are no dead fish in neighbouring tanks, to avoid buying sick individuals. Since this is a rare species, ask the seller about the fish's origin and current care conditions.