Daisy's Ricefish is a tiny neon-blue species from Muna Island, perfect for nano tanks. Peaceful, hardy, and easy to breed in home aquariums.
Overview
Daisy's Ricefish (Oryzias woworae) is a small freshwater fish from the family Adrianichthyidae, described relatively recently in 2010. Its natural range is limited to streams and small bodies of water on Muna Island, located off the southeastern coast of Sulawesi in Indonesia. This restricted habitat is what sometimes earns it the name Muna Ricefish.
Adults reach only 3-4 cm in length, making them one of the most compact aquarium fish available. Males display a stunning neon-blue body coloration with vivid red-orange accents on their fins and chest area. Females are more subdued, with a grayish-yellow body and a subtle blue sheen. With proper care, their lifespan in aquariums is 2-3 years.
Thanks to their peaceful temperament, striking coloration, and low maintenance needs, Oryzias woworae has become one of the most popular fish for nano aquariums. They should be kept in groups of at least 8-10 individuals — in a school, they feel more confident, display more vibrant behavior, and males actively show off to one another.
Tank Requirements
The minimum tank volume for a small group is 20 liters, but for comfortable keeping of 10-12 specimens, a 40-liter tank or larger is preferable. The aquarium should be densely planted with live vegetation: Java moss, hornwort, najas, cryptocorynes, and floating plants (water lettuce, riccia) will provide natural shelter and the diffused lighting these fish prefer.
Optimal water parameters are: temperature 24-28°C, pH 6.5-7.5, and general hardness (GH) 5-15. Filtration should be gentle — an internal sponge filter or air-driven filter works best. Strong currents are undesirable, as these fish naturally inhabit calm areas of water bodies. A dark substrate is recommended, as it makes the neon coloration of the fish look especially striking.
A tight-fitting lid is essential: ricefish are excellent jumpers and may leap out of the water at the slightest stress.
Feeding and Diet
In the wild, Oryzias woworae feeds on small insects, their larvae, zooplankton, and microalgae. In the aquarium, they readily accept a variety of small-sized foods.
The staple diet can consist of high-quality micro pellets or crushed flakes designed for small tropical fish. However, to maintain vibrant coloration and good health, live or frozen foods should be offered regularly: baby brine shrimp, microworms, daphnia, and cyclops. These foods are especially important when conditioning fish for breeding.
Feed twice daily in small portions that the fish consume within 2-3 minutes. Ricefish feed primarily at the water surface and in the middle layers, so sinking foods are less suitable. A fasting day once a week benefits their digestion.
Care and Maintenance
Despite being easy to care for (care level 2 out of 5), Oryzias woworae requires stable water parameters. Sudden fluctuations in temperature and water chemistry can lead to stress and disease. Weekly water changes of 20-25% are essential. When performing water changes, it is important to use water that has been prepared to match the tank's temperature and hardness.
The filter should be rinsed in removed tank water every 2-3 weeks. Regularly test ammonia, nitrite, and nitrate levels — these small fish are sensitive to elevated nitrogen compounds. Nitrate levels should ideally be kept below 20 mg/l.
Live plants not only beautify the aquarium but also help maintain biological balance by absorbing nitrates. With proper care, ricefish remain active, display vivid coloration, and spawn regularly.
Compatibility
Oryzias woworae is an exceptionally peaceful fish (aggression level 1 out of 5), making it an excellent choice for community nano tanks. Ideal tank mates are equally peaceful species of similar size: Chili Rasboras, Celestial Pearl Danios, Ember Tetras, Sparkling Gouramis, and Harlequin Rasboras.
Good bottom-dwelling companions include Kuhli Loaches and small Corydoras species, which will occupy the lower levels of the tank. Dwarf shrimp (Neocaridina) also make excellent tank mates, although the fish may eat newborn shrimplets.
Under no circumstances should ricefish be kept with large or aggressive fish such as cichlids, large barbs, or paradise fish. Any active, fast-swimming fish will stress these calm little creatures and outcompete them for food.
Breeding
Breeding Oryzias woworae is not particularly difficult (difficulty level 2 out of 5) and often occurs spontaneously in a well-maintained species tank. Sexual dimorphism is clearly pronounced: males are brighter, slimmer, and have larger, more elongated dorsal and anal fins. Females are plumper, paler in color, and have a rounded belly.
To stimulate spawning, slightly raise the water temperature to 26-28°C and increase the proportion of live foods in their diet. Spawning typically occurs in the morning hours. After fertilization, the female carries a cluster of eggs near her anal opening for some time before attaching them to fine-leaved plants such as Java moss or spawning mops.
Parents may eat their own eggs, so plants with attached eggs should be moved to a separate container filled with water from the main tank. Incubation lasts 10-14 days at 26°C. The newly hatched fry are very small and initially feed on infusoria and microworms. After about a week, they can be transitioned to baby brine shrimp. Fry grow quickly and develop adult coloration by 2-3 months of age.