Goldfish is a small fish in a relatively long life. Its life span is not only related to the breed and its own health, but also depends on the feeding situation. Different varieties of goldfish, its life span is also different. Under normal conditions, their life span can reach 6 to 7 years. If raised in good conditions and kept healthy, some can live for 10 years or more. So far, the oldest goldfish can live for 43 years.
As the fish grows up, its scales will also change. As the fish grows, rings of growth form on its scales. Therefore, the age of fish can be inferred by observing the distribution and number of growth rings on the scales. Because the scales are small and reflective, no growth ring can be seen by direct observation. So you need to use tweezers to remove the scales from the fish, and then use a microscope to observe them.
Under the microscope, you can see that there are darker lines on the scales, which is its growth ring. Every time a fish gets a year old, it adds a line to its scales. So the number of lines represents the age of the fish. In addition to observing the scales to determine its age, it can also be judged by the length of the fish. However, this method is not accurate because the body length of fish is affected by environmental and feeding factors.
