It is the result of an acquired calcium deficiency after growing into a fish of a certain size. Fish and other animals, but also due to a variety of reasons such as the environment (such as tank farming), autosomal defects (such as digestive tract damage), the clear waters of the lack of food feed caused by calcium chondropathy, first of all, the hardness of the fish bone will affect the shape, the formation of deformities that are different from the common fish. This condition is common in aquarium-bred ornamental fish due to improper feeding. In serious cases, it will form a curved tail, collapsed skull and so on. Of course, it does not affect people's consumption and safety, no need to worry.