Sources and image credits

Research sources

• All Japan Nishikigoi Promotion Association: Variety - variety names and Nishikigoi classification reference.
• All Japan Nishikigoi Promotion Association: Nishikigoi overview - modern Nishikigoi history and cultural context.
• Ojiya City: Nishikigoi - regional history and Niigata/Ojiya cultural context.
• Yamakoshi regional information - Niigata mountain-village context connected with Nishikigoi culture.
• Zen Nippon Airinkai: Varieties of Nishikigoi - show appreciation groups and major variety categories.
• Kyorin Hikari: Nishikigoi variety guide - Japanese-language variety reference and koi education context.
• Matsuda Koi Farm: variety introduction - Japanese-language descriptions of major varieties.
• FAO aquaculture manual: carp seed production context - general carp breeding, egg, fry, and nursery-management background.
• FAO: Fish culture in undrainable ponds, nutrition section - carp nutrition, supplementary feeding, protein requirement factors, and pond-culture feeding context.
• FAO: The nutrition and feeding of farmed fish and shrimp - complete and supplementary diet context, protein level interpretation, and pond-feeding limitations.
• SRAC Publication No. 5003: Principles of Fish Nutrition - fish nutrition principles, digestible energy, protein, ingredient quality, and feeding-practice context.
• Hikari Wheat-Germ Formula information - koi wheat-germ feeding context and guidance to adjust feeding by water temperature and fish activity.
• Hikari Sales USA: Feeding coldwater koi basics - coldwater koi feeding, small portions, and seasonal feeding caution.
• Fiverkoi: What is a koi pond drum filter? - rotary drum filter / RDF visual reference for koi pond mechanical filtration.
• Surrey Koi: K1 moving bed filter - moving bed biological filtration visual reference.
• Ricky Stoddart: Using shower filters in your koi pond - shower and trickle filtration visual reference.
• The Pond Guy: PowerUV UV Clarifier - UV clarifier visual reference for green-water control.
• Merck Veterinary Manual: Routine Health Care of Fish - health management focus on water quality, nutrition, sanitation, and quarantine.
• Merck Veterinary Manual: Disorders and Diseases of Fish - fish disease context, stress, water quality, parasites, and professional treatment guidance.
• Merck Veterinary Manual: Parasitic Diseases of Fish - parasite diagnosis, microscopy, and koi/goldfish parasite context.
• Merck Veterinary Manual: Bacterial Diseases of Fish - bacterial ulcer, fin, eye, dropsy, and koi Aeromonas reference context.
• Merck Veterinary Manual: Mycotic Diseases in Aquaculture - Saprolegnia and other fungal/water-mold disease context.
• Merck Veterinary Manual: Normal Reference Ranges for Routine Water Quality Analysis - routine fish water-quality ranges used as a professional reference point.
• University of Florida IFAS: Ammonia in Aquatic Systems - ammonia chemistry, toxicity, pH, and temperature context for fish systems.
• University of Florida IFAS: Ichthyophthirius multifiliis infections in fish - white spot disease background and management context.
• University of Florida IFAS: Argulus fish louse infections - fish lice life cycle and ornamental fish parasite context.
• University of Florida IFAS: Lernaea anchorworm infestations - anchor worm life cycle and management context.
• University of Florida IFAS: Introduction to Fish Health Management - practical fish-health management, prevention, and diagnostic context.
• University of Florida IFAS: Use of Antibiotics in Ornamental Fish Aquaculture - antibiotic stewardship and sensitivity-testing context.
• University of Florida IFAS: Koi Herpesvirus Disease - koi biosecurity, quarantine, viral disease, and laboratory-testing context.
• Merck Veterinary Manual: Viral Diseases of Fish - viral disease context for aquarium and pond fish.
• Southern Regional Aquaculture Center: Nitrite in Fish Ponds - nitrite toxicity and management guidance for pond fish.
• Mississippi State University Extension: pH and Alkalinity - alkalinity, hardness, and pH stability background for pond management.
• FDA: Ich treatment for ornamental finfish - regulatory update on Ich treatment availability for ornamental fish.
• Amazon Associates: affiliate disclosure help - disclosure requirements for affiliate links.
• FTC Endorsement Guides FAQ - material connection and affiliate disclosure guidance.
• Baidu Baike: 蝴蝶鲤 - Chinese-language overview of butterfly koi naming and appearance.
• Baidu Baike: 锦鲤 - Chinese-language overview of koi/carp cultural and historical context.
• Baidu Jingyan aquarium keeping articles - Chinese hobbyist context on tank-raised ornamental fish care, water changes, and filtration habits.

Book references used for editorial direction

• Herbert R. Axelrod, A Complete Introduction to Koi and Garden Pools - koi keeping, feeding, breeding, garden pools, and variety terminology context.
• Barry James, A Fishkeeper's Guide to Koi - pond construction, filtration, buying, quarantine, seasonal care, breeding, and varieties.
• Dennis Kelsey-Wood and Tom Barthel, Garden Ponds: Basic Pond Setup and Maintenance - pond setup, water chemistry, maintenance, and garden pond context.
• David Pool, Hobbyist Guide to Successful Koi Keeping - koi husbandry, filtration, quarantine, water quality, and practical pond management.
• Dick Mills, How to Care for Your Koi - beginner-friendly koi care and routine keeping context.
• Nancy Cooper Wisner and others, Keeping Koi - koi pond care, water quality, filtration, and variety reference context.
• George C. Blasiola, Koi: Everything About Care, Nutrition, Diseases, Pond Design and Maintenance - care, feeding, disease, pond design, and aquatic plant context.
• Gregory Skomal, Koi - beginner care, water quality, filtration, and variety context.
• Richard D. Bartlett and others, Koi for Dummies - beginner koi care, pond planning, common problems, and practical hobbyist routines.
• Zuza Vrbova and Hugh Nicholas, Koi for Ponds - pond-focused koi care and variety overview.
• Herbert R. Axelrod, Koi Varieties: Japanese Colored Carp/Nishikigoi - variety terminology, classification, and visual appreciation context.
• Peter Cole, The Art of Koi Keeping - water quality, selection, parasite awareness, and display-oriented husbandry context.
• Anne McDowall, The Tetra Encyclopedia of Koi - broad reference for koi care, varieties, pond design, health, and display.
• William G. Coleman and Ken Rust, Water Clarity Secrets for Ponds and Water Gardens - water clarity, filtration, and maintenance context.

Editorial note: My Koi Garden keeps a private koi book library for topic discovery and fact-checking, but published copy is paraphrased rather than quoted. Six newly added Chinese-language koi books are still in intake review because automated extraction did not recover usable body text, so they are not yet being used for specific factual claims on public pages.

Professional video references

• Sacramento Koi: Koi Pond Water Testing Made Simple - embedded in the beginner koi care guide for water-testing workflow context.
• Sacramento Koi: 20 Questions To Ask Yourself Before You Build a Koi Pond - embedded in the pond guide for planning context.
• Sacramento Koi: How to backwash the Advantage Bead Filter - embedded in the filtration systems page for maintenance context.
• Sacramento Koi: 5 Guidelines to Selecting Quality Koi - Conformation - embedded in the choose koi guide for body-shape evaluation context.
• Sacramento Koi: 5 Guidelines to Selecting Quality Koi - Scale Type - embedded in the koi varieties guide for scale-type recognition context.
• Sacramento Koi: How to Safely Add a New Koi to Your Pond - embedded in the koi care hub for acclimation and new-fish risk context.

Image credits

• Award-winning variety reference photos: KoiShowNews: 55th All Japan Nishikigoi Show awards. Local copies are used on variety pages so images remain stable and open as high-resolution references.
• Chinese koi pond and courtyard pond photos: Pexels Nanjing koi pond photographs, Wikimedia Commons ornamental ponds in China, PxHere koi pond photo, and Sina garden pond design images listed in the local source manifest.
• Kohaku image: Martin Kammerer, CC BY-SA 4.0, via Wikimedia Commons.
• Taisho Sanke image: Paulman, CC BY-SA 3.0, via Wikimedia Commons.
• Showa image: Aquafanatic, CC BY-SA 3.0, via Wikimedia Commons.
• Yamabuki Ogon image: Benutzer:Fehlwort, CC BY-SA 3.0, via Wikimedia Commons.
• Tancho image: Maxikoi, CC BY-SA 3.0, via Wikimedia Commons.
• Utsurimono image: Maxikoi, CC BY-SA 3.0, via Wikimedia Commons.
• Bekko image: Maxikoi, CC BY-SA 3.0, via Wikimedia Commons.
• Asagi image: Maxikoi, CC BY-SA 3.0, via Wikimedia Commons.
• Koi history garden image is AI-generated artwork created for My Koi Garden, based on Chinese garden, tai chi, bamboo, water, and koi cultural motifs.
• Dedicated koi pond photo: Captain-tucker, CC BY-SA 3.0, via Wikimedia Commons.
• Garden koi pond photo: FossilDS, CC0, via Wikimedia Commons.
• Planted koi pond photo: Forest and Kim Starr, CC BY 3.0 US, via Wikimedia Commons.
• Raised formal pond photo: Richard Humphrey, CC BY-SA 2.0, via Wikimedia Commons.
• Homepage gallery, Portland Japanese Garden koi pond: Tony Webster, CC BY 2.0, via Wikimedia Commons.
• Homepage gallery, Japanese garden stone lantern koi pond: Savannah Rivka, CC BY-SA 4.0, via Wikimedia Commons.
• Homepage gallery, koi at Japanese Garden, UH Manoa: Daniel Ramirez, CC BY 2.0, via Wikimedia Commons.
• Homepage gallery, Hakone Gardens koi pond: Grendelkhan, CC BY-SA 4.0, via Wikimedia Commons.
• Homepage gallery, colorful koi carp close view: Bernard Spragg. NZ, public domain, via Wikimedia Commons.
• Ich / white spot fish disease photo: ML5 at English Wikipedia, public domain, via Wikimedia Commons.
• Anchor worm fish disease photo: G Sowmith reddy, CC BY-SA 4.0, via Wikimedia Commons.
• Ergasilus gill parasite photo: Andreas R. Thomsen, CC BY-SA 3.0, via Wikimedia Commons.
• Saprolegnia fish disease photo: Velela, CC BY 3.0, via Wikimedia Commons.
• Columnaris disease gill photo: Aquatic Animal Health Program, public domain, via Wikimedia Commons.
• Historical fish lesion photo: H. S. Davis / Freshwater and Marine Image Bank, public domain, via Wikimedia Commons.
• Historical fin infection photo: H. S. Davis / Freshwater and Marine Image Bank, public domain, via Wikimedia Commons.
• kohaku real photo 1: Kohaku nishikigoi Konishi Koi Farm Martin Kammerer ID7185- - Martin Kammerer, CC BY-SA 4.0, via Wikimedia Commons.
• kohaku real photo 2: Koi - The original uploader was Necrophorus at German Wikipedia., CC BY-SA 3.0, via Wikimedia Commons.
• sanke real photo 1: Sanke - Maxikoi, CC BY-SA 3.0, via Wikimedia Commons.
• sanke real photo 2: Sanke2 - Maxikoi, CC BY-SA 3.0, via Wikimedia Commons.
• showa real photo 1: Showa vom Züchter Isa - Robsig12, CC BY-SA 3.0, via Wikimedia Commons.
• showa real photo 2: Showa2 - Maxikoi, CC BY-SA 3.0, via Wikimedia Commons.
• tancho real photo 1: Tanchosanke - Maxikoi, CC BY-SA 3.0, via Wikimedia Commons.
• tancho real photo 2: TANCHO SHOWA 1 - Jean louis cristini, CC BY-SA 4.0, via Wikimedia Commons.
• utsurimono real photo 1: Shiro Utsuri - Maxikoi at Dutch Wikipedia Later version(s) were uploaded by Erik Baas at nl.wikipedia. (Original text: nl:Overleg gebruiker:Maxikoi), CC BY-SA 3.0, via Wikimedia Commons.
• utsurimono real photo 2: Ginrinshiroutsuri - Maxikoi, CC BY-SA 3.0, via Wikimedia Commons.
• bekko real photo 1: Doitsubekko - Maxikoi, CC BY-SA 3.0, via Wikimedia Commons.
• bekko real photo 2: Six koi - User:Stan Shebs, CC BY-SA 3.0, via Wikimedia Commons.
• asagi real photo 1: Koi asagi - No machine-readable author provided. Rob Hille assumed (based on copyright claims)., Public domain, via Wikimedia Commons.
• asagi real photo 2: Asagi - Maxikoi, CC BY-SA 3.0, via Wikimedia Commons.
• ogon real photo 1: Yamabuki Ogon - Benutzer:Fehlwort, CC BY-SA 3.0, via Wikimedia Commons.
• ogon real photo 2: Yamabuki Ogon koi and reflections in pond at Japanese Friendship Garden in Balboa Park - Lhimec, CC0, via Wikimedia Commons.
• longfin real photo 1: Butterfly Koi - Dslcards, CC BY-SA 4.0, via Wikimedia Commons.
• longfin real photo 2: Doitsu Hariwake Hirenaga - Koilover68, CC BY-SA 4.0, via Wikimedia Commons.
• shusui real photo 1: Shusui - Maxikoi, CC BY-SA 3.0, via Wikimedia Commons.
• shusui real photo 2: Six koi - User:Stan Shebs, CC BY-SA 3.0, via Wikimedia Commons.
• goshiki real photo 1: Goshiki classique - Ducoussetl, CC BY-SA 4.0, via Wikimedia Commons.
• goshiki real photo 2: Goshiki moderne - Ducoussetl, CC BY-SA 4.0, via Wikimedia Commons.
• kujaku real photo 1: Kujaku2 - Maxikoi, CC BY-SA 3.0, via Wikimedia Commons.
• kujaku real photo 2: Doitsukujaku - Maxikoi, CC BY-SA 3.0, via Wikimedia Commons.
• doitsu real photo 1: Doitsu Sanke - Benutzer:Fehlwort, CC BY-SA 3.0, via Wikimedia Commons.
• doitsu real photo 2: Doitsushowa - Maxikoi, CC BY-SA 3.0, via Wikimedia Commons.
• ochiba real photo 1: Ochibashigure - Maxikoi, CC BY-SA 3.0, via Wikimedia Commons.
• ochiba real photo 2: Koi - The original uploader was Necrophorus at German Wikipedia., CC BY-SA 3.0, via Wikimedia Commons.
• ginrin real photo 1: Gin Rin Showa - Maxikoi at Dutch Wikipedia Later version(s) were uploaded by Erik Baas at nl.wikipedia. (Original text: nl:Overleg gebruiker:Maxikoi), CC BY-SA 3.0, via Wikimedia Commons.
• ginrin real photo 2: Ginrinshiroutsuri - Maxikoi, CC BY-SA 3.0, via Wikimedia Commons.
• chagoi real photo 1: Groei Chagoi... Groeeeeei! - KoiQuestion, CC BY-SA 2.0, via Wikimedia Commons.
• chagoi real photo 2: Chagoi Hirasawa 88cm - KoiQuestion, Creative Commons, Some rights reserved, via Flickr.
• goromo real photo 1: Budo Goromo - Maxikoi at Dutch Wikipedia, CC BY-SA 3.0 / GFDL, via Wikimedia Commons.
• hikari-utsuri real photo 1: Best in Variety Hikari Utsuri - KoiQuestion, Creative Commons, Some rights reserved, via Flickr.

Images from professional breeders, Japanese associations, and dealer websites are not copied unless the license or permission allows reuse. Future sales pages should use original product photos or photos supplied with explicit permission.

Koi variety real-photo credits

• Koi asagi (asagi) photo by No machine-readable author provided. Rob Hille assumed (based on copyright claims)., Public domain. Source.
• Asagi (asagi) photo by Maxikoi, CC BY-SA 3.0. Source.
• Doitsubekko (bekko) photo by Maxikoi, CC BY-SA 3.0. Source.
• Six koi (bekko) photo by User:Stan Shebs, CC BY-SA 3.0. Source.
• Groei Chagoi... Groeeeeei! (chagoi) photo by KoiQuestion, CC BY-SA 2.0. Source.
• Chagoi Hirasawa 88cm (chagoi) photo by KoiQuestion, Creative Commons, Some rights reserved. Source.
• Doitsu Sanke (doitsu) photo by Benutzer:Fehlwort, CC BY-SA 3.0. Source.
• Doitsushowa (doitsu) photo by Maxikoi, CC BY-SA 3.0. Source.
• Gin Rin Showa (ginrin) photo by Maxikoi at Dutch Wikipedia Later version(s) were uploaded by Erik Baas at nl.wikipedia. (Original text: nl:Overleg gebruiker:Maxikoi), CC BY-SA 3.0. Source.
• Ginrinshiroutsuri (ginrin) photo by Maxikoi, CC BY-SA 3.0. Source.
• Budo Goromo (goromo) photo by Maxikoi at Dutch Wikipedia, CC BY-SA 3.0 / GFDL. Source.
• Maruju Ai Goromo 47cm (goromo) photo by KoiQuestion, CC BY-SA 2.0. Source.
• Maruyju Budo Goromo (goromo) photo by KoiQuestion, CC BY-SA 2.0. Source.
• Goshiki classique (goshiki) photo by Ducoussetl, CC BY-SA 4.0. Source.
• Goshiki moderne (goshiki) photo by Ducoussetl, CC BY-SA 4.0. Source.
• Best in Variety Hikari Utsuri (hikari-utsuri) photo by KoiQuestion, CC BY-SA 2.0. Source.
• Hi Utsuri (hikari-utsuri) photo by Benutzer:Fehlwort, CC BY-SA 3.0 / GFDL. Source.
• Kohaku nishikigoi Konishi Koi Farm Martin Kammerer ID7185- (kohaku) photo by Martin Kammerer, CC BY-SA 4.0. Source.
• Koi (kohaku) photo by The original uploader was Necrophorus at German Wikipedia., CC BY-SA 3.0. Source.
• Kujaku2 (kujaku) photo by Maxikoi, CC BY-SA 3.0. Source.
• Doitsukujaku (kujaku) photo by Maxikoi, CC BY-SA 3.0. Source.
• Butterfly Koi (longfin) photo by Dslcards, CC BY-SA 4.0. Source.
• Ochibashigure (ochiba) photo by Maxikoi, CC BY-SA 3.0. Source.
• Koi (ochiba) photo by The original uploader was Necrophorus at German Wikipedia., CC BY-SA 3.0. Source.
• Yamabuki Ogon (ogon) photo by Benutzer:Fehlwort, CC BY-SA 3.0. Source.
• Yamabuki Ogon koi and reflections in pond at Japanese Friendship Garden in Balboa Park (ogon) photo by Lhimec, CC0. Source.
• Sanke (sanke) photo by Maxikoi, CC BY-SA 3.0. Source.
• Sanke2 (sanke) photo by Maxikoi, CC BY-SA 3.0. Source.
• Showa vom Züchter Isa (showa) photo by Robsig12, CC BY-SA 3.0. Source.
• Showa2 (showa) photo by Maxikoi, CC BY-SA 3.0. Source.
• Shusui (shusui) photo by Maxikoi, CC BY-SA 3.0. Source.
• Six koi (shusui) photo by User:Stan Shebs, CC BY-SA 3.0. Source.
• Ginrin Sora Showa (soragoi) photo by KoiQuestion, CC BY-SA 2.0. Source.
• Koi (soragoi) photo by The original uploader was Necrophorus at German Wikipedia., CC BY-SA 3.0. Source.
• Tanchosanke (tancho) photo by Maxikoi, CC BY-SA 3.0. Source.
• TANCHO SHOWA 1 (tancho) photo by Jean louis cristini, CC BY-SA 4.0. Source.
• Shiro Utsuri (utsurimono) photo by Maxikoi at Dutch Wikipedia Later version(s) were uploaded by Erik Baas at nl.wikipedia. (Original text: nl:Overleg gebruiker:Maxikoi), CC BY-SA 3.0. Source.
• Ginrinshiroutsuri (utsurimono) photo by Maxikoi, CC BY-SA 3.0. Source.
• Show-grade koi additions
• Yonsai Yuki Asagi Yamaju (asagi) photo by KoiQuestion, CC BY-SA 2.0. Source.
• Marigold Sanke, 65th Nagaoka Koi Show coverage (sanke) photo by KoiQuestion, CC BY-SA 2.0. Source.
• Supreme Champion Raad Sanke (sanke) photo by KoiQuestion, CC BY-SA 2.0. Source.
• Isa Showa prize-winning reference (showa) photo by KoiQuestion, CC BY-SA 2.0. Source.
• Nisai Showa Sekiguchi (showa) photo by KoiQuestion, CC BY-SA 2.0. Source.
• Tancho Showa Marusada 64 cm (tancho) photo by KoiQuestion, CC BY-SA 2.0. Source.
• Best in Variety Hikari Muji (ogon) photo by KoiQuestion, CC BY-SA 2.0. Source.
• Soragoi 2 (soragoi) photo by KoiQuestion, CC BY-SA 2.0. Source.
• Doitsu Hariwake Hirenaga (longfin) photo by Koilover68, CC BY-SA 4.0. Source.
• Longfin (longfin) photo by Wikimedia contributor, CC BY-SA 3.0. Source.