Karasu-goi is a primitive variety of koi that is completely black all over, with both ornamental and breeding value

Karasu-goi is a primitive variety of koi, and its most striking feature is that the whole body is jet black, with no red, white or other mottled markings visible on the head, back, fins or tail. A high-quality Karasu-goi has a deep black, glossy body color, neatly arranged scales and a calm, powerful swimming posture; as it moves through the pond it looks like a streak of flowing ink, making it highly ornamental.

Karasu-goi is a representative of the black koi lineage, with a relatively ancient bloodline, and it holds an important place in koi breeding. It is often used as a parent fish in crossbreeding and improvement, and some koi varieties dominated by black-and-white tones have incorporated Karasu-goi blood in their breeding process. When selecting one, individuals with evenly distributed black color, no browning and no white spots mixed in are best.

In terms of keeping, the habits of Karasu-goi are similar to those of ordinary koi; it prefers water rich in dissolved oxygen and clear in quality, and keeping the water temperature relatively stable is more conducive to the depth of its body color. In daily care, you can feed koi-specific compound feed, appropriately supplemented with natural bait, stick to regular feeding in fixed amounts, change the water regularly, and keep the filtration system running normally.

Karasu-goi has a strong constitution, but it can likewise suffer from common parasitic diseases such as white spot disease, trichodina and anchor worm, and special attention is needed when the seasons change or the water temperature fluctuates sharply. Normally, new water should be aged and fish quarantined before entering the pond, and the fish body and appetite should be observed frequently; if abnormalities are found, isolate and treat them early, and Karasu-goi can remain healthy for the long term.