There are many reasons for goldfish to lose scales. For example, bacterial infection, parasites, scratches, etc. can cause goldfish to lose scales, so it is necessary to treat the specific reasons for goldfish to lose scales. If it is caused by bacterial infection or parasites, the owner needs to clean and disinfect the fish tank, change the water regularly, keep the fish tank clean, and occasionally let the goldfish bask in the sun, which is beneficial to the growth of fish scales. If it is caused by injury, it is necessary to prevent the goldfish from being injured again. It is best to keep them separately first.