Youkihi medaka are the strain that makes people stop and ask “what IS that?” when they see them in an outdoor tub. The name means “sun-lit” or “evening sun” in Japanese, and it describes their coloration perfectly — a warm, saturated orange that glows in natural sunlight like embers in a fire. Of all the medaka strains available in the US market, Youkihi are the most visible from a distance, making them the ideal choice for patio ponds where you view fish from above at arm’s length.
What Makes Youkihi Distinct
Youkihi medaka carry a genetic combination that produces orange-red pigmentation across the entire body. Unlike wild-type medaka (which are translucent olive-grey) or Miyuki medaka (which are metallic blue-silver), Youkihi are warm-toned fish that read as bright orange in natural light.
The orange coloration in Youkihi comes from xanthophores (yellow pigment cells) and erythrophores (red pigment cells) combined with reduced melanophore (dark pigment) expression. The result is a fish where warm pigments dominate without dark pigment obscuring them.
Quality grading in Youkihi:
- Standard grade — overall orange body with some translucent patches on the belly
- High grade — solid, uniform orange from head to tail including the belly
- Premium grade — deep, saturated orange approaching red, with no pale areas
- Lame (metallic) Youkihi — orange body with added metallic sheen from lame genes; the most expensive variant
Tank and Pond Setup
Youkihi are identical to other medaka strains in their care requirements — they are extremely adaptable and hardy. The setup considerations are more about displaying their color optimally.
Parameters:
| Parameter | Range |
|---|---|
| Temperature | 64–82°F (18–28°C) |
| pH | 6.5–8.0 |
| GH | 4–12 dGH |
| KH | 2–10 dKH |
| Ammonia/Nitrite | 0 ppm |
Substrate for color: Youkihi look best on dark substrate — the contrast between dark background and bright orange fish is striking. In outdoor tubs, black nursery containers or dark-colored stock tanks show Youkihi better than tan or grey containers. For indoor tanks, black sand or dark gravel is ideal.
Lighting: Natural sunlight produces the most vivid coloration. This is another reason Youkihi excel in outdoor setups — no artificial light replicates the color intensity that direct or filtered sunlight achieves. Indoor tanks should use full-spectrum LEDs at moderate to high intensity.
Outdoor Keeping in USDA Zones 7-9
Youkihi medaka are outstanding outdoor fish for the South’s climate. The March-through-October pond season aligns perfectly with medaka’s active temperature range.
Seasonal Timeline
March (startup):
- Move fish outdoors once water temperature stabilizes above 65°F
- Start with light feeding (once daily) as metabolism ramps up
- Introduce floating plants for cover and spawning substrate
April-May (breeding begins):
- As temperatures pass 72°F and daylight exceeds 12 hours, spawning starts
- Females carry egg clusters daily; deposit them on moss, mops, or plant roots
- Collect eggs if you want to maximize fry production; leave them for natural colony growth
June-August (peak season):
- Fish are most active, most colorful, and spawning daily
- Monitor water temperature — shade the container if water exceeds 86°F
- Feed twice daily; supplement with live foods for best color and condition
- Fry from early season spawns are growing rapidly
September-October (wind-down):
- Spawning slows as daylight hours shorten below 12
- Reduce feeding as temperatures drop below 72°F
- Stop feeding entirely if water drops below 60°F
- Plan indoor housing before first cold snap
November-February (indoor):
- Bring fish inside before sustained temperatures below 55°F
- Indoor holding can be as simple as a 10-gallon tank with a sponge filter
- Maintain at 68-72°F with moderate feeding
- No breeding pressure during winter rest
Container Recommendations
Youkihi shine in these outdoor setups:
- Black Rubbermaid stock tanks (50-100 gallon) — excellent thermal mass, dark interior shows off orange color
- Half whiskey barrels with liner — classic look, 25-30 gallon capacity
- Large ceramic pots (glazed, no drain hole) — decorative option for patios
- Concrete mixing tubs — cheap, large capacity, can be painted dark inside
Stocking for outdoor tubs:
- 50-gallon stock tank: 15-20 adult Youkihi
- 30-gallon barrel: 8-12 adults
- 100-gallon stock tank: 25-35 adults
Feeding Youkihi
Medaka are surface feeders with small mouths. Feed floating foods that stay at the top where the fish eat:
- Hikari Medaka food (the Japanese import formulation) — best overall medaka food
- Crushed high-quality flake — Hikari, NorthFin, or Xtreme Nano ground to powder consistency
- Live baby brine shrimp — excellent for conditioning breeders and enhancing orange color
- Freeze-dried daphnia — floats well, appropriate size for adult medaka
- Live mosquito larvae — free protein source in outdoor ponds (the fish actively hunt them)
Color-enhancing foods: Youkihi orange coloration can be enhanced with foods containing astaxanthin and other carotenoids. Brine shrimp, Spirulina-based foods, and color-enhancing flakes will deepen the orange over time. The difference between a well-fed Youkihi and a poorly-fed one is dramatic — deep orange versus washed-out pale orange.
Breeding
Youkihi breed exactly like all other medaka strains — prolifically and easily once conditions are right.
Triggering spawning:
- Temperature above 72°F (ideally 75-80°F)
- Daylight exceeding 12 hours (natural outdoor light or artificial timer)
- High-protein diet with live or frozen foods
- Clean water with regular partial changes
Egg management:
- Females produce egg clusters each morning, attached near the anal vent
- Eggs are deposited on fine-leaved plants, spawning mops, or moss within hours
- Collection: pull eggs from the mop/plant or pluck directly from the female
- Incubation: 10-14 days at 75-80°F in clean water
- Add a drop of methylene blue to incubation water to prevent fungus
Fry care:
- Feed powdered fry food, vinegar eels, or newly hatched BBS from day one
- Fry grow rapidly — visible orange coloration appears at 4-6 weeks
- Separate fry by size to prevent larger fish from outcompeting smaller ones
- First coloration grading is possible at 8-10 weeks
Breeding for Deeper Orange
To improve orange saturation in your Youkihi line:
- Grade juveniles at 8-10 weeks — keep only the most intensely colored fish
- Both males AND females carry color genetics — select vibrant females too
- Color-enhancing diet during development intensifies genetic expression
- Dark container backgrounds help you grade accurately (fish show true color on dark backgrounds)
- Cull or rehome pale fish to prevent diluting the gene pool
Tankmates
Youkihi medaka are peaceful and mix well with:
- Other medaka strains (will interbreed — separate if maintaining pure lines)
- Neocaridina shrimp (adults coexist, medaka may eat very small shrimplets)
- Amano shrimp
- Snails (nerite, mystery, ramshorn)
- Endlers and guppies (similar size and temperament)
- White Cloud Mountain Minnows
Avoid: Anything large enough to eat them, anything with long fins that they might nip (rare but possible with male bettas), and aggressive species.
Youkihi vs. Other Orange/Red Medaka Strains
| Strain | Color | Metallic | Price Range | Availability |
|---|---|---|---|---|
| Youkihi (standard) | Solid orange | No | $5-$8 per fish | Common |
| Youkihi Lame | Orange + metallic sheen | Yes | $10-$20 per fish | Moderate |
| Orange Sparkle | Orange + scattered glitter | Yes | $8-$15 per fish | Moderate |
| Red Cap | White body, red/orange head | No | $8-$12 per fish | Less common |
Youkihi are the most affordable and available orange medaka strain, which makes them the best starting point for outdoor pond keepers. If you fall in love with orange medaka (you will), the lame and sparkle variants are natural upgrades for your second or third season.
Why I Recommend Youkihi for First-Time Pond Keepers
Three reasons:
-
Visibility. The bright orange makes them easy to spot, count, and observe in outdoor containers. You can check on your fish from across the patio without walking over to the tub.
-
Hardy genetics. Youkihi are one of the older established medaka strains, meaning the genetics are stable and the fish are robust. Newer, fancier strains can be more delicate due to intensive inbreeding for rare traits.
-
Affordability. At $5-$8 per fish (or less if you buy from local breeders), Youkihi are cheap enough to start a colony without a major investment. If you lose a few during the learning curve, it is not financially painful. Within one outdoor season of breeding, you will have more Youkihi than you started with regardless.
Start with 8-10 Youkihi in a dark-colored outdoor tub, add floating plants, feed them well, and watch the colony grow. By the end of your first pond season, you will understand why Japanese hobbyists have been keeping medaka outdoors for hundreds of years.