Wazumi Medaka
Wazumi Medaka is a black-and-white improved medaka variety valued for its striking contrast. First bred in 2019, it's a relatively recent addition to the medaka world, distinguished by the depth and staying power of its black markings. Most medaka patterns can fade through a "background response," changing shade to match their surroundings, but Wazumi's black is classified separately and resists this kind of fading. In its lineage, it continues the line of black-bodied medaka that don't show this background response. Rated as suited to keepers with some prior experience, Wazumi rewards those who want to enjoy stable, well-defined markings over time.
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- Variety Name
- Lineage
- Actual Photos
- Color Classification
- Body Type
- Scale Type
- Size
- Origin
- Age/Generation
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Wazumi 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
- Because the black does not fade, the pattern stays clear even in a white container. The difference from background-responsive mottling shows plainly in a white container, so judge the fish in a light-coloured one. The Medaka Web Encyclopedia recommends outdoor keeping and suggests shading half the container in summer.
- 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
- For selection, move the fish to a white container and confirm the black does not fade. Mottling that fades with the background response is classed separately, so depth of pattern and resistance to fading are the criteria.
About Wazumi Medaka
Wazumi Medaka is a black-and-white improved medaka variety bred in 2019, prized for its deep, fade-resistant black markings. Suited to keepers with some experience, it grows to a maximum of about 4cm.
7 things to know before welcoming a Wazumi Medaka
1Deep, Fade-Resistant Black
Wazumi's biggest draw is how deep and stable its black markings are. The color holds its intensity over time, keeping the pattern crisp and well-defined.
2Distinct from Background Response
Many medaka change shade through a mechanism called the "background response," adjusting to the color of the tank's substrate or walls. Wazumi's black markings are classified separately from ordinary background-responsive patterns and are less affected by this kind of environmental color shift.
3Bred in 2019
Wazumi was first bred in 2019, making it a relatively new addition among medaka varieties. It's placed in the lineage of black-bodied medaka that don't show the background response.
4Suited to Experienced Keepers
Wazumi is rated as suited to keepers with some prior experience. Having a grasp of basic medaka care beforehand makes it easier to notice changes in coloring or condition.
5Grows to About 4cm
Wazumi reaches a maximum standard length of about 4cm as an adult. That's comparable to other improved medaka varieties, so it's worth considering size differences if keeping it alongside other fish.
6Enjoying the Contrast
The clear contrast of black against white is Wazumi's main visual appeal. Keeping it alongside other improved medaka varieties makes it easy to compare and appreciate the differences in coloring.
7Watch Beyond Color Alone
With many medaka, a shift in body color can be a clue to their condition, but since Wazumi's black resists fading, it helps to also watch things like swimming behavior and appetite when checking on its health.
Frequently asked questions about Wazumi Medaka
- Q.How big does Wazumi Medaka grow?
- A.Wazumi grows to a maximum standard length of about 4cm as an adult, a fairly typical size among improved medaka varieties.
- Q.Is Wazumi Medaka suitable for beginners?
- A.Wazumi is rated as suited to keepers with some prior experience rather than complete beginners. Having a foundation in basic medaka care makes it easier to notice changes in its coloring or condition.
- Q.Will Wazumi's black markings fade over time?
- A.Wazumi's black markings are known for resisting fading, unlike ordinary medaka patterns that can lighten through the background response. That said, appearance may still vary somewhat between individuals.
- Q.What lineage does Wazumi Medaka belong to?
- A.Wazumi is positioned in the lineage of black-bodied medaka that don't show the background response. It's a relatively new variety, first bred in 2019.
- Q.Is Wazumi Medaka subject to CITES?
- A.Wazumi Medaka is not subject to CITES.
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