What are the small balls on the glass inside your aquarium?

Answer 1

Its quite possible that they are eggs if they are transparent or cloudy in colour. If they are all together in a bunch id say its from a snail. But if they are scattered around the tank like on the glass and ornaments and plants id say that u have a laying goldfish. If this is the case and u want them to hatch try not to disturb them. Hope this helps :oD