between Koi carp and red carp is that both Koi carp and red carp belong to Cyprinidae, but Koi carp is artificially cultivated, and there are many kinds of colors, such as red, white and black. Red koi carp is a mutation of wild carp, which leads to red body color, so red carp has only one color of red. But red carp is the original species of koi, even now, koi occasionally appear red in the process of reproduction, but this will generally be eliminated, because pure red is not as good as multi-color ornamental.
between koi and goldfish 1, different varieties: although goldfish and koi are similar, and are bred after the acquired mutation. But koi is a variety of carp, goldfish is a variety of crucian carp, the two categories are different.
2, the appearance is different: First of all, the tail, Koi are usually single-tailed, some are double-tailed. But most goldfish have two tails, and some variants even have three or four tails. Secondly, the body length of koi can reach 50 centimeters, while goldfish are generally about 20 centimeters, there are individual species, such as grass goldfish, the largest can only grow to 30-40 centimeters. Finally is the beard, the goldfish does not have the beard, moreover the goldfish's mouth is upward. Koi fish have whiskers on both sides of their mouths, and their mouths are downward.
