What Is the Difference Between Koi and Grass Goldfish? A Quick Guide to Telling Them Apart

Koi are a high-end ornamental fish popular around the world today, praised as living gems in the water and swimming works of art. Grass goldfish are the ancestors of goldfish, with a body shape and tail fin the same as ordinary crucian carp, slender and short, suitable for keeping in large park ponds. But do you know what the differences between koi and grass goldfish are? Let's take a look together below!

Koi

Koi have a robust build, brilliant colors, varied patterns, and a majestic swimming posture, with extremely high ornamental and keeping value. Their body length can reach 1-1.5 m, and their colors include one to three colors, including white, yellow, orange, red, black and blue (a light gray shadow presented by black under the scales). The colors can be matte or glossy. Although the patterns have endless variations, the best patterns are a small round spot on top of the head and a stepped-stone pattern on the back. The scales may be present or absent, large or small, or wrinkled, just like “diamonds”.

Grass Goldfish

Grass goldfish are commonly known as red crucian carp or golden crucian carp. The body is spindle-shaped, the tail fin is not forked, and the dorsal, ventral, pectoral and anal fins are all normal. They have a strong constitution, strong adaptability, a wide range of foods, and are easy to keep. Besides red, their body colors also include red-and-white, calico and others. They are suitable for large-scale keeping in parks and natural waters, and can also be kept in courtyard tanks and ponds as well as in aquariums.

The Difference Between Koi and Grass Goldfish

1. Those with barbels are koi; grass goldfish do not grow barbels.

2. Those that are all white with a red top of the head are koi; if there is a fleshy growth on the head, whether red or not, it is a grass goldfish.

3. Koi have a plump, round body shape, while grass goldfish are relatively flatter by comparison.

4. The dorsal fin of koi is set slightly farther back, while that of grass goldfish is set farther forward.