Bronze Medaka
Bronze Medaka is an improved medaka variety with a black body tinged with amber, overlaid with a spreading bronze-colored external glow. Bred in 2019 by Masaharu Tarumi, it descends from the Rinko line and belongs to a group known as the "Rinketsu" (scale lineage) strains. A shared hallmark of this lineage is "isshuko," where the glow wraps all the way around to the belly, giving the fish a subdued yet striking shimmer that shifts with the angle of light. It's considered a variety suited to intermediate keepers rather than complete beginners. Its understated coloration stands out even alongside flashier varieties, adding depth to any collection.
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- Variety Name
- Lineage
- Actual Photos
- Color Classification
- Body Type
- Scale Type
- Size
- Origin
- Age/Generation
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Bronze 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
- External luminescence and the wrap-around sheen read best from above, so a dark container viewed from the top suits this variety. Outdoors, guard against summer overheating with shade 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
- The extent and colour of external luminescence vary considerably between individuals, and the line is maintained by repeated selection. 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 Bronze Medaka
Bronze Medaka is an improved variety with an amber body and spreading bronze external glow. Part of the 2019 Rinko lineage, known for its all-around glow. Suited to intermediate keepers.
7 things to know before welcoming a Bronze Medaka
1Suited to Intermediate Keepers
Bronze Medaka is rated as suited to intermediate keepers rather than absolute beginners. Having some experience with routine water changes and water quality management helps bring out its bronze glow more reliably. It's a good next step after you've gained some basic medaka-keeping experience, rather than a first fish.
2Descended from the Rinko Line
Bronze Medaka was bred in 2019 by Masaharu Tarumi as a derivative of the Rinko line, placing it within a group known as the Rinketsu (scale lineage) strains. Knowing this background makes it easier to understand how it relates to similar lineage varieties.
3The "Isshuko" Glow Reaching the Belly
A trait shared across this lineage is "isshuko" — an external glow that wraps around to cover the belly as well. Because the glow can be appreciated from both a top-down and side view, arranging your tank layout and viewing angle thoughtfully will bring out its appeal even more.
4Adult Size Up to About 4cm
Even as adults, they stay compact at up to about 4cm in standard body length. This makes it easier to plan your tank space and consider layouts when keeping multiple fish together in the same container.
5Watch for Sudden Water Changes
As with medaka in general, sudden temperature swings or deteriorating water quality can affect their condition. Take care to acclimate them gradually during water changes, and pay extra attention to temperature fluctuations during seasonal transitions.
6Prepare Your Tank Before Bringing Them Home
Before bringing them home, it's important to have the basics ready — a tank, dechlorinated water, and a thermometer. After arrival, be sure to take enough time for acclimation so they can settle into their new environment.
7A Viewing Setup That Shows Off the Glow
Because the bronze glow changes expression depending on how light hits it, choosing a spot mindful of sunlight or lighting direction lets you enjoy the coloration more fully. The background color of the tank also affects how the glow appears.
Frequently asked questions about Bronze Medaka
- Q.Can beginners keep Bronze Medaka?
- A.Bronze Medaka is rated as suited to intermediate keepers. Having some basic experience with medaka care will help you enjoy keeping them more successfully.
- Q.How big does Bronze Medaka grow?
- A.Even as an adult, it stays compact at up to about 4cm in standard body length, making it easy to plan your tank space around.
- Q.What's the origin of the name "Bronze"?
- A.The name comes from its bronze-colored external glow spreading across an amber-tinged black body. It was bred in 2019 by Masaharu Tarumi as a derivative of the Rinko line.
- Q.What is the "isshuko" trait?
- A.Isshuko refers to a glow pattern where the external light wraps around to cover the belly as well. It's a trait shared across the Rinketsu lineage that Bronze Medaka belongs to.
- Q.Are there any legal restrictions on keeping Bronze Medaka?
- A.Bronze Medaka is not subject to CITES. There are no special legal restrictions on keeping it.
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