Kuro Miyuki (Black Miyuki) Medaka

Kuro Miyuki (Black Miyuki) Medaka key facts

Care level

Intermediate

Lifespan

2-3 years

Size

Up to about 4cm SL

Temperature

18〜28℃

Diet

Prepared medaka food, green water

Lighting

Black body colour shows background adaptation: in a dark container the colour tightens and the contrast with the sheen sharpens, while a pale container washes the black out. The luminescence appears on the back, so the fish is best viewed from above. Outdoors, summer sun raises water temperature sharply, so shade half the container with something such as a reed screen.

Diet & Nutrition

Commercial prepared medaka food is the staple, given in an amount finished within a few minutes. Leftovers decay and foul the water, so adjust the quantity. Green water rich in phytoplankton suits fry rearing.

Water Temperature & Quality

Slightly acidic to slightly alkaline water is considered ideal, and the water drifts toward acidic as keeping continues. Around one water change per week is the guideline, and because sudden shifts in temperature or pH cause stress, acclimatise new fish by floating the bag. FishBase records the wild water chemistry of this species as pH 7.0-8.0 and hardness 9-19 dH.

Tank Mates & Compatibility

A peaceful schooling fish, normally kept as a group of the same variety. One litre of water per fish is the guideline against overcrowding; overstocking causes poor growth, reduced breeding, oxygen shortage and water fouling.

Breeding

Outdoors the spawning season runs from about April to October, once water reaches 18C or above with 12-13 hours of daylight. For year-round indoor breeding, 25-28C water and over 13 hours of lighting are the guideline. Eggs hatch at a cumulative 250 degree-days, about 10 days at 25C.

Health & Notes

Because of background adaptation the same fish looks different depending on the container, so grade fish in a single container. The Medaka Web Encyclopedia notes that luminescence on a black body reads gold or deep blue rather than the bluish-white of blue and white fish, so do not expect the tone of blue miyuki. Outdoors the fish become inactive and overwinter near the bottom as water cools, resuming activity in spring once daytime water exceeds 10C. A 0.3-0.5% salt bath is used for ailing fish, with water raised to no more than about 28C.

About Kuro Miyuki (Black Miyuki) Medaka

Kuro Miyuki (Black Miyuki) medaka pairs a black body with golden or deep-blue Miyuki luster and a color-shifting background response. Intermediate-level to keep, growing to about 4cm as an adult.

7 things to know before welcoming a Kuro Miyuki (Black Miyuki) Medaka

1. 1Color Shifts With the Container

   Kuro Miyuki shows a background response, meaning its color depth changes with the color of its container. Keeping it in a dark-colored tank tends to deepen the black, while a light-colored tank can make the color appear paler. Choosing your container thoughtfully can help bring out its best coloring.

2. 2Golden and Deep-Blue Shimmer

   While white and blue medaka show a pale, bluish-white shine, Kuro Miyuki's Miyuki-derived luster sits on top of a black body, making it appear golden or deep blue depending on the light. Viewing it from different angles or under different lighting reveals different expressions of its color.

3. 3Best Suited to Intermediate Keepers

   Maintaining Kuro Miyuki's striking coloration calls for more attention to water quality and light conditions, so it's generally considered suited to intermediate keepers. It's a good idea to have some general medaka-keeping experience before bringing one home.

4. 4Compact Size, Up to About 4cm

   Even as adults, Kuro Miyuki stay compact, reaching a standard body length of up to about 4cm. This modest size makes them easy to keep even in smaller containers.

5. 5Avoid Sudden Water Changes

   Medaka are hardy fish, but they can be sensitive to sudden shifts in water temperature or quality. Take your time acclimating new arrivals, and be especially careful during seasons when daily temperature swings are large.

6. 6Choose Calm Tankmates

   Kuro Miyuki has a calm temperament, so if you keep it with other fish, choose similarly sized, peaceful tankmates. Keeping it alone also works well if you want to closely observe its changing colors.

7. 7Prepare Your Tank Before Arrival

   Before bringing your Kuro Miyuki home, set up its container, water, and food in advance. If you want to enjoy its color-shifting nature to the fullest, consider using a dark-colored container as one option.

Frequently asked questions about Kuro Miyuki (Black Miyuki) Medaka

Q.What does Kuro Miyuki's coloring look like?

A.It combines a black body with the shimmering luster inherited from the Miyuki line. While white and blue medaka show a pale, bluish-white shine, that same luster appears golden or deep blue against Kuro Miyuki's dark body.

Q.How difficult is it to keep?

A.Kuro Miyuki is generally considered suited to intermediate keepers. Maintaining its striking coloration is easier with some prior experience in basic water quality management.

Q.How big does it grow?

A.As an adult, it reaches a standard body length of up to about 4cm. Like other medaka varieties, it stays a compact size.

Q.Does the tank color affect its coloring?

A.Yes. Kuro Miyuki shows a background response, so its color depth shifts depending on the color of its container. Dark-colored containers tend to bring out a richer, deeper color.

Q.Is Kuro Miyuki subject to any special regulations?

A.Kuro Miyuki is not subject to CITES. You can enjoy keeping it just like any other medaka variety.

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