koi fish are colorful varieties of carp that are often kept in outdoor ponds and water gardens. They are known for their vibrant colors, patterns, and graceful swimming. Koi can grow quite large, sometimes reaching lengths of over three feet, and they can live for many years, with some living over 200 years. Originating from Japan, koi fish are often associated with good fortune and prosperity. They come in various colors, including orange, white, black, and yellow, and are bred for their unique patterns. Koi are social creatures and thrive in groups, making them popular among fish enthusiasts.