Youkihi Medaka
Oryzias latipes var. 'Youkihi'
Min Tank Size
20L
Adult Size
4 cm
Lifespan
3 years
School Size
6+
About
Named after Yang Guifei, one of the four great beauties of ancient China, Youkihi Medaka carries that namesake seriously. A cultivated variety of Oryzias latipes, these fish display a deep reddish-orange body that practically glows under good lighting, especially once they've matured and settled into a healthy diet. They originated from Japan's long medaka breeding tradition, and Youkihi is considered one of the foundational fancy varieties that kicked off widespread hobbyist interest in the genre.
They're tiny fish, rarely cracking 3.5 cm, but they punch well above their size in visual impact. The coloration is most intense on well-fed adults under warm, indirect light, and it genuinely deepens over time rather than fading like some ornamental strains.
Water parameters are refreshingly forgiving. They tolerate a wide temperature band, handle both soft and moderately hard water, and don't demand pristine conditions to thrive. pH anywhere from 6.5 to 8.0 works fine, which makes them compatible with most tap water setups without much chemistry intervention.
Feeding is simple. Quality flake or micro pellet covers the basics, but regular offerings of baby brine shrimp, daphnia, or frozen bloodworm will deepen their color and encourage spawning. They're surface-oriented feeders, which makes mealtimes easy to observe.
As a community fish, they're undemanding and genuinely peaceful. They coexist beautifully with other small, non-aggressive species and do particularly well in planted tanks where dense vegetation mimics their natural rice paddy and slow-stream habitat. If you want to see how other hobbyists are keeping Youkihi, browse the tank builds here for real setup inspiration.
Water Parameters
Temperature
°CpH
GH
dGHKH
dKHSwimming Level
Flow Preference
Keeping multiple Youkihi Medaka together
Youkihi Medaka are shoaling fish and need company of their own kind. Keep a group of at least 6. Smaller groups leave them stressed, washed-out in color, and prone to hiding.
Compatibility
These fish work well with similarly sized, slow-water species. Good pairings include other medaka varieties, small rasboras like chili or exclamation point rasboras, pygmy corydoras, and ember tetras. They're shrimp and snail safe, making them a go-to choice for planted community tanks with Neocaridina colonies. Avoid housing them with anything large enough to eat them, nippy species like tiger barbs or serpae tetras, or fast aggressive feeders that will outcompete them at meal time. In a 40-liter or larger planted tank they fit naturally into a peaceful multi-species setup without much management needed.
Commonly kept with
Species this one is most often paired withCommonly tried but avoid
Often paired, but shouldn't beCare Notes
The most common beginner mistake is underfeeding or feeding only dry flake, which results in washed-out coloration and reduced spawning activity. They need variety. Another frequent issue is not managing breeding output. These fish spawn year-round and eggs hatch readily, so a tank can become overcrowded quickly if you're not removing eggs or separating fry. Keep a lid on the tank, as they're more prone to jumping than their size suggests. They prefer gentle filtration, and a strong flow can stress them or exhaust smaller individuals.
Behavior & Aggression
Youkihi Medaka are peaceful by default, but males can become persistently pushy toward females during spawning activity, which is essentially constant. A male chasing a single female relentlessly is common and can stress or even injure her over time. This isn't aggression in the traditional sense, more like enthusiastic mating pressure that doesn't self-regulate. Mild territorial displays between males occasionally occur, usually just flaring and circling without contact. Keeping a balanced ratio with more females than males goes a long way toward diffusing this.
Things to Know
- Prolific egg scatterer, remove eggs or expect uncontrolled breeding
- Males can harass females relentlessly, keep balanced sex ratios
- Capable jumpers, use a tight-fitting lid
- Color fades without quality diet including live or frozen foods
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