What are these white little dots in my fish tank on the glass?

I would like to get more goldfish but there are these white little dots that appear never go away. They haven’t always been an issue I noticed them around the same time I got a goldfish who ended up being sick and passing away this also needed up killing my other fish. I think they had anchor worms and I tried treating it but lost them both this was about 4 months ago and these white dots are in the tank even tho I have been doing water changes and scraping them off. The white dots seem some kind microorganism and seem move if you stare at them very closely. I want these gone before I can get a new fish.