I keep an Indonesian red dragon, which often loses its scales these days.

Changing water too much will cause scale, scale caused by trauma, or what caused by parasites. You should find out for yourself first. If it's trauma that causes desquamation, don't say it. It is best to use as little disinfectant as possible. More importantly, food hygiene depends on your careful observation and whether other scales that have not fallen off have changed. It is very important to raise the temperature. Pay attention to hygiene, feed more high-protein food, or add two injections of vitamin B 12, and it will be fine soon.