Tomoki Medaka (Oryzias latipes) 2-2.5 cm

Overview

The Tomoki Medaka, Oryzias latipes tomoki, is a charming Japanese rice fish known for its hardiness, active schooling behaviour and suitability for smaller aquariums. Offered here at 2-2.5 cm, these juveniles are ideal for aquarists looking for a peaceful, low-maintenance fish with plenty of character. Medaka are often chosen for planted nano tanks, species setups and even seasonal outdoor tubs in suitable weather, thanks to their adaptability and calm nature.

With their slender bodies, lively swimming style and subtle beauty, Tomoki Medaka make a rewarding choice for beginners and experienced keepers alike. They are not demanding fish, but they do best when kept in a stable, well-maintained aquarium with gentle filtration and plenty of cover. At Tropical Fish Co, we carefully pack livestock for fast UK delivery, and every order is supported by our live arrival guarantee for peace of mind.

These fish are best kept in groups, where their natural behaviour can be observed as they explore the upper and middle levels of the tank. Their small adult size and modest requirements make them a great option for planted community aquariums, breeding projects and compact home setups.

Care at a Glance

Origin & Natural Habitat

Oryzias latipes is native to East Asia, particularly Japan, Korea and parts of China, where it inhabits slow-moving waters such as rice paddies, ditches, ponds, marshes and shallow streams. The species has become famous for its resilience and ability to tolerate a range of conditions, which is one reason medaka are so popular in the aquarium hobby.

The Tomoki line is a cultivated form associated with the species and is kept for its attractive appearance and dependable temperament. In nature, medaka live in shallow, plant-filled environments with access to surface cover and calm water. This background explains their preference for gentle flow, open swimming space and dense planting in the aquarium.

Because they are adapted to relatively shallow, variable habitats, medaka are often more forgiving than many tropical fish. That said, they still benefit from clean water, regular maintenance and a stable environment. Their natural behaviour is most visible when they are kept in a group in a well-planted tank with soft lighting and areas of floating vegetation.

Tank Setup & Water Parameters

A planted aquarium is the best home for Tomoki Medaka. A 40-litre tank is suitable for a small group, though larger tanks are always better for long-term stability and more natural behaviour. Use a tight-fitting lid, as medaka can jump, especially when startled or during feeding.

Provide gentle filtration with low to moderate flow. Sponge filters, small internal filters or air-driven systems are all excellent choices. The tank should include open swimming areas along with fine-leaved plants, mosses, floating plants and perhaps a few pieces of driftwood or smooth stone. These features help reduce stress and give the fish places to rest and explore.

Water parameters should remain stable rather than chasing exact numbers. A temperature range of 18-26°C is suitable, with many keepers finding them comfortable at typical room temperatures if the tank is kept stable. Aim for a pH between 6.5 and 8.0, with clean, well-oxygenated water and low ammonia and nitrite at all times. Regular partial water changes are important, especially in smaller aquariums.

For aquascaping, think natural and lightly structured. Medaka appreciate plants near the surface and along the sides of the tank, leaving the centre open for swimming. They can also be kept in outdoor tubs in appropriate climates, but any outdoor setup must be protected from predators and extreme temperature swings.

Feeding Guide

Tomoki Medaka are omnivores and will readily accept a variety of foods. A high-quality micro pellet or small flake can form the staple diet, supplemented with frozen or live foods such as daphnia, baby brine shrimp, grindal worms and mosquito larvae where appropriate. They also benefit from occasional plant-based matter and foods with spirulina or other vegetable ingredients.

Feed small amounts once or twice daily, only as much as they can consume in a couple of minutes. Overfeeding can quickly affect water quality in smaller tanks, so it is better to keep portions modest. Juveniles, such as the 2-2.5 cm fish offered here, may appreciate slightly more frequent feedings while they grow.

A varied diet supports colour, growth and breeding condition. If you plan to breed medaka, conditioning with live and frozen foods can help prepare adults for spawning. As with all fish, remove uneaten food promptly and maintain good filtration and regular maintenance.

Tank Mates / Compatibility

Tomoki Medaka are peaceful and best suited to other calm species that will not outcompete or harass them. Good tank mates include small rasboras, ember tetras, pygmy corydoras, peaceful shrimp, snails and other similarly sized, non-aggressive fish. They also do well in a species-only setup, which is often the simplest and most natural option.

Avoid large, boisterous or predatory fish, as well as fin-nippers and species that require much warmer water. Fast, aggressive tank mates can stress medaka and reduce their confidence, while very large fish may see them as food. If keeping them with shrimp, provide plenty of plant cover so juveniles have places to hide.

Because medaka spend much of their time near the surface and upper water column, choose companions that occupy different areas of the tank and share similar water preferences. A calm, planted community is the ideal environment for these fish.

Why Buy from Tropical Fish Co

At Tropical Fish Co, we focus on healthy livestock, careful packing and a smooth customer experience from order to arrival. Your Tomoki Medaka are shipped with fast UK delivery and backed by our live arrival guarantee, giving you confidence when buying fish online.

We select stock with care and aim to provide clear, practical information so you can set up the right home for your fish before they arrive. Whether you are building a peaceful nano aquarium, a planted display or a breeding project, Tomoki Medaka are a rewarding and resilient choice. Their gentle nature, manageable size and attractive behaviour make them a favourite among aquarists who value simplicity without sacrificing interest.

Order with confidence and enjoy one of the most adaptable small fish available for the home aquarium.