The lion head is a goldfish, not a tropical fish. If you have raised tropical fish before and have ulcers on their bodies, it is not recommended to change the water. It will easily cause changes in water temperature and quality and aggravate the condition... It is best to heat the fish to 30 degrees, use yellow powder, and stop eating. If the fish is really hungry just looking at it It is very flat, feed some dry feed, never live food, as the bacteria carried by live food will also aggravate the condition. Also...don’t release fish if they are sick!