My green terror had hole in the head and I succesfully treated it in its early stages by at first, performing 2-3 30% water changes for 1 week and after treating the tank with metro+ (just follow directions on the back), small amounts of uniodized salt, and bumping the tempreture up to 80 degrees Fahrenheit. I'm not sure if the tempreture and salt helped but the green terrors activity increases at higher tempreture so he was eating more in warmer water, diet is an important part in curing. Feed top shelf foods such as hikari or nls.