Basic
At what water temperature do koi look their most beautiful?
Generally, after a period of rapid growth throughout spring, summer, and autumn, koi tend to display their best condition when the water temperature drops to around 15–20°C in autumn. During this time, the white ground (shiroji), black patterns (sumi), and red patterns (hi) all appear in optimal form—vibrant, crisp, and...
What is the difference between a koi with a "large frame" and one that is "fat"?
A koi described as having a "large frame" mainly refers to its inherent skeletal structure—broad skull, elongated snout, strong backbone, and a solid overall framework. This type of build is not simply a result of weight or plumpness, but stems from genetic potential and developmental capacity. A large-framed koi usually...
Where exactly should a koi's "high back" be located?
The standards for evaluating koi body shape have evolved over time. The pursuit of a "high back" emerged in the process of emphasizing muscularity in koi. Initially, the "high back" referred to a pronounced elevation at the shoulder and back area, as exemplified by the raised, muscular koi bred in the...
How to Understand "Show-Grade Koi"?
The term "show-grade" can be interpreted in two distinct ways: Broadly speaking, "show-grade" refers to koi that are considered eligible for entry into competitions. Such fish typically meet basic entry requirements, such as having no obvious physical defects, possessing reasonably attractive coloring and patterns, and displaying healthy swimming posture. They...
How to Understand the Concept of "Tategoi" in Koi?
In the koi industry, the term "Tategoi" refers to a koi that possesses future potential and developmental promise. This means the fish is not yet an exceptionally outstanding specimen in the present, but based on various signs—such as body structure, skin quality, pattern potential, and growth trajectory—it is judged to...
What is the best quality of sumi in three-colored koi?
Three-colored koi include white-based Sanke (Taisho Sanke) and black-based Sanke (Showa Sanshoku). Within the industry, blue-toned sumi is considered the finest. It is valued for its unique aesthetic appeal and elegant appearance, creating a deep, vivid, and powerful visual effect. Under sunlight, blue sumi reflects subtle light, adding a distinct...
At what age does the sumi (black markings) of koi generally stabilize?
The sumi in koi typically begins to stabilize around four to five years of age, though this can vary depending on lineage and individual traits. What patterns or trends are observed in the changes of sumi in koi? The development of sumi is influenced by variety, bloodline, and environmental temperature,...
Is Studying Koi Bloodlines Important for Koi Enthusiasts?
Yes, it is essential. A koi bloodline refers to a family lineage of koi that carries stable genetic traits. Studying koi bloodlines involves understanding the consistent hereditary characteristics of each lineage. For those aiming to appreciate or pursue high-quality, top-tier koi, knowledge of bloodlines is indispensable: while outstanding bloodlines do...
Can a koi's scales grow back if they fall off?
Yes, in most cases, dropped scales can regrow. As long as the injury is not too severe, the new scale will generally grow back and be almost identical to the original. However, if the underlying dermis is damaged, the new scale may grow in deformed or may not regrow at...
What is Koi Hibernation?
When the water temperature drops to around 8°C (koi typically stop feeding at 10°C), the fish exhibit behaviors like lining up and resting at the bottom of the pond. Simultaneously, their respiratory rate slows, and their metabolic activity decreases significantly—marking the onset of hibernation. Koi hibernation is a non-memory-based conditional...
Is it possible for female koi to lay eggs in a pond without males?
Yes, it is still possible. This phenomenon, known as "spontaneous spawning" or "stress-induced ovulation," occurs when female koi undergo significant physiological stress. Even in the absence of males, a mature female may release eggs if exposed to intense stimuli such as: Transportation stress: Long-distance transport, especially with changes in water...
What are the main causes of a "bulging belly" (so-called "airplane belly") in koi?
Genetics is the number one cause. Here, it cannot even be explained as a matter of "bloodline" or lineage, as fish exhibiting a pronounced bulging belly typically do not belong to well-bred, high-grade (bloodline) stock. In non-specialized or less professional koi farms, breeders often select broodstock with larger abdomens in...
Recent Post
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Where exactly should a koi's "high back" be located?
Jul 28, 2025 -
How to Understand "Show-Grade Koi"?
Jul 24, 2025 -
How to Understand the Concept of "Tategoi" in Koi?
Jul 23, 2025 -
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Can a koi's scales grow back if they fall off?
Jul 18, 2025 -
What is Koi Hibernation?
Jul 16, 2025
