At the moment my fish get not exactly the best brand of food, I want to change to a better brand. I've been looking at pro-gold, but I've found nothing about shipping outside the US. The other brands (like Hikari, Omega one) that people like are also impossible to find here in Belgium. Anyone has had the same problem? Or has an idea?

The best food I've seen so far is Tetra.

Goldfish keeping is not something new in your country. In fact, I know one international ranchu judge from Belgium. His name is Geert Coppens and if you can contact him you will find a source for good goldfish food
The pic of some of his fish

If you type his name in google, you will find a lot of info about him.

Somehow I only find info about his fish and several other people with the same name. The fact that one of the best-known Belgian stand up comedians has the same name isn't exactly helping.

type his name in qoutes thne type like goldfish or something by his name to narrow the field