parasites in loaches

Help! I have 3 yoyo loaches and 9 neons in a 10 gall tank. I know! It’s bad but hear me out. I do water changes 1-2 a week and there haven’t been a problem for 2 months. I’ll transfer them when I can afford a larger tank. But recently my yoyos are flashing against decor and gravel. They just...