Ricefish & Medaka Care Guide: Tank Setup, Feeding, and Breeding
Ricefish, also known as medaka, are charming little nano fish that have become favorites for planted tanks, patio ponds, and beginner-friendly setups. Native to the rice paddies and slow waters of East Asia, these hardy, peaceful schoolers come in a rainbow of selectively bred colors and tolerate a wide range of conditions, which makes them forgiving and fun to keep. This guide covers everything you need to know to keep ricefish thriving, from tank and outdoor setup to water parameters, feeding, breeding, and tankmates. You can browse our full ricefish collection and wider nano fish selection to see what is currently available.
What Are Ricefish and Medaka?
Ricefish belong to the genus Oryzias, with the Japanese medaka (Oryzias latipes) being the most familiar in the hobby. They are small, typically reaching about an inch to an inch and a half, with upturned mouths suited to feeding at the surface. Decades of selective breeding, especially in Japan, have produced a stunning array of varieties, from the metallic Platinum Miyuki Medaka with its glowing blue-white back to the soft blue sheen of Daisy's Blue Ricefish. They are shoaling fish that feel most secure and show their best color in groups of six or more.
Tank and Outdoor Setup
Ricefish are wonderfully adaptable and do well both indoors and outside. A group is happy in a planted nano tank of around 5 to 10 gallons, and they truly shine in larger setups or seasonal patio ponds during warm months. Explore our nano aquariums for an indoor display, or a larger option from our glass aquariums for a bigger shoal. They love planted environments, so add floating plants for cover and spawning sites, along with easy low-light plants and other live aquatic plants. A gentle filter and calm water suit them best, since they are not strong swimmers and dislike heavy current.
Water Parameters and Care
One of the biggest appeals of ricefish is how hardy and temperature-tolerant they are. They thrive in cool to moderately warm water and often do fine at room temperature without a heater, tolerating a broad pH and hardness range. That said, clean, stable water is still key to long-term health. Always treat tap water with a water conditioner, test regularly with a reliable test kit, and keep up with routine aquarium maintenance and water changes. Because they handle cooler temperatures so well, ricefish are an excellent choice for unheated nano tanks and outdoor tubs in mild seasons.
Feeding Ricefish
Ricefish are omnivores that feed primarily at the surface, so floating and slow-sinking foods work best. A quality micro-pellet or finely crushed flake makes a great staple, and you can round out their diet with small live or frozen foods like daphnia, baby brine shrimp, and microworms for color and conditioning. Browse our aquarium fish food selection, including fish food flakes, and feed small amounts once or twice a day, offering only what the fish can finish quickly. Their tiny mouths mean food should be appropriately sized.
Breeding Medaka and Ricefish
Ricefish are among the easiest egg-laying fish to breed, which is part of why they are so beloved. In good conditions with plenty of light and warmth, females carry a cluster of eggs near the vent before depositing them onto plants or spawning mops. The adults will eat their own eggs and fry, so move eggs or floating plants to a separate container to raise the babies. Fry are tiny and need very fine foods like infusoria or powdered fry food at first. With warmth, clean water, and dense floating plants, a healthy group will often produce a steady supply of young through the warmer months.
Tankmates and Temperament
Ricefish are peaceful, gentle, and well suited to calm community and nano setups. They mix beautifully with other small, non-aggressive species and make excellent companions for invertebrates. Consider pairing them with freshwater shrimp and a snail cleanup crew, which share their love of planted, gently filtered tanks. Avoid large or boisterous fish that may bully or outcompete them, and stick to similarly sized, mild-mannered tankmates from our freshwater fish selection. For first-time keepers, ricefish themselves are a great entry into our beginner fish lineup.
Frequently Asked Questions
Are ricefish and medaka the same thing? Yes, medaka is the common name for Japanese ricefish (Oryzias latipes), and the terms are often used interchangeably for the many selectively bred color varieties.
Do ricefish need a heater? Usually not. They are cold-tolerant and often do well at room temperature, which makes them ideal for unheated nano tanks and seasonal outdoor tubs.
How many ricefish should I keep together? Keep them in groups of at least six. They are shoaling fish that feel more secure and display better color when kept in numbers.