Picture gene & lineage tree
Visual pedigree of breeder-reported inputs, where available. Dashed arrows represent documentary claims or selection history, not DNA-tested genes.
This strain's direct parent lines are not established by the reviewed sources. No breeding cross, genotype or inheritance pattern is implied. Source: Sources remain under review; ancestry connections will appear only with cited evidence.
Identification and naming
The archived Medaka Kōbō Edo listings name Code Sea, including March 23, 2026, item 6249 and April 10, 2026, item 7517. Both are attributed to seller Aqua Shop Enishi (アクアショップ縁), and both display 神話めだかブリード, meaning bred by Shinwa Medaka. These are independent listing events for a named Japanese trade line, not independent genetic confirmations. Neither listing establishes the original naming authority or first release year.
Provenance: producer, seller and creator
Aqua Shop Enishi is the selling business named on the auctions. Shinwa Medaka is the breeding operation credited on those two auctions. A Japanese retail directory also lists Shinwa Medaka in Izumo, Shimane Prefecture and identifies its Instagram handle as shinwamedaka1. The directory is secondary evidence for a public-facing contact, not breeder testimony about Code Sea genetics.
New lead (seller attribution; not independent original-breeder confirmation): A search-indexed public Instagram caption from Aqua Shop Enishi (@enishi18) reads Code Sea 作出者 関口直樹氏 ... 神話めだかブリード 上見、横見, crediting Naoki Sekiguchi (関口直樹) as creator and separately describing the pictured sale stock as Shinwa Medaka-bred. The exact Instagram post permalink was not recoverable during this review; do not overstate this excerpt as a first-person account. Medaka Kōbō Edo's own ABOUT pag
Appearance and diagnostic limitations
A small top-view photograph supplied for internal research appears to show golden-yellow to olive/green metallic shine, darker outlines between reflective areas and pronounced dorsal reflection. Because color balance, lighting angle, video compression, size, sex and side-view characteristics were not controlled, these are preliminary image observations, not confirmed strain-wide standards.
Phenotype categories meriting source review include exterior light (体外光, continuous dorsal reflectance), lame (ラメ, dispersed glittering scale plates), fin light (ヒレ光) and long-fin morphology. These are distinct Japanese descriptive categories. There is no sufficient breeder evidence to claim Code Sea necessarily carries one or more of them or descends from visually similar Green, Ryokkou or Emerald Fin stocks.
Official classification cross-check (2025 JMA, not a Code Sea certification)
The Japan Medaka Association (JMA) currently publishes its fifth-edition ornamental-medaka variety classification manual (September 2025) with a corresponding phenotype inventory, rather than relying on the older 2022/2024 guidance. The manual distinguishes the breeder's house/trade nickname from diagnostic phenotype classifications. This is an appropriate trait vocabulary and inspection framework, not proof of Code Sea parentage or JMA recognition.
For Code Sea, a specimen-by-specimen research examination should document
1. Standardized top-view images on light and dark backgrounds to assess how body-color/background response may influence the apparently gold–olive-green appearance. Note camera white balance, visible illumination and juvenile/adult stage.
Reported creator's separate documented work (not ancestral evidence)
A Japanese improved-Medaka nickname reference credits Naoki Sekiguchi of Medaka Farm Izumi (then associated with Marugen) with development of Ulysses (ユリシス), reported released in February 2021. That directory describes Aurora Yellow Lame, Tsukiyumi and Sapphire among the Ulysses inputs, with blue lame in the phenotype. This supports Sekiguchi's broader breeding history but does not support inserting Ulysses or any of its ancestors into Code Sea's pedigree. Nor does it establi
Genetics and source-honest lineage tree
Original parent lines not documented. No source-backed founding pair, intermediate crossing generations, Mendelian dominance/recessivity, sex-linkage, F2 ratio, penetrance, fixation percentage or named causal gene has been established for Code Sea.
The required public picture gene tree should show a named Code Sea child/target node and an unknown-parents panel, with NO arrows to any invented parent strain. Attribution of offered stock to Shinwa Medaka belongs in provenance, not in the gene genealogy.
Ornamental-medaka genomic research reports candidate genes for multiple named phenotypes, but none of that work assigns a causal allele to the Code Sea trade designation.
Care, breeding and grading
No specific water temperature, pH, dissolved-mineral target, feeding supplement or disease-resistance difference for Code Sea has been established. General Japanese Medaka care and routine quarantine are more defensible than invented Code Sea-specific husbandry. Photographic grading should document top and lateral views of the same fish under comparable illumination, proportion/health, reflective coverage, fin formation and consistent expression in offspring. A commercial “hi
Trade history and availability
Earliest located listing: March 23, 2026, two pairs, auction ID 6249. Another listed two pairs April 10, 2026, ID 7517. Archived auction prices are dynamic figures, not proof of final completed sale or a general market valuation.
An independent export quotation described approximately 20 juveniles as “high-grade” at ¥3,000 each and indicated Japan-to-Thailand carriage. The quotation is not evidence that all Code Sea fish have that price or that the specific photographed fish came from Shinwa Medaka. An import/export quote does not establish import permissions or current stock availability.
Breeder follow-up and photo permission
Ask the original breeder contact through an independently verified Medaka Farm Izumi/Naoki Sekiguchi business channel to confirm whether he created Code Sea, his founding crosses, generation chronology, the year and meaning of the name, traits, stability and permitted photographic use. Ask Shinwa Medaka separately whether its batches descend from Sekiguchi's original stock and whether breeder documentation exists. The retailer @enishi18 can supply an exact public post permali
Public research references
Listed research leads are not automatically supporting evidence for every individual claim.