They're at the surface - if you have floating plants they'll often be among the leaves, but if not my fishies usually pick a corner or just blow them aganist a side. They're created by the fish coating an air bubble with saliva to hold it together, and the blowing it back out - many of these lil bubbles creates quite a pile!
I have an underground filter and it covers the surface with bubbles. Do you have to have a bubblenest to breed bettas & if you do is it bad that i have all those bubbles covering the top
Yes, you need to have a bubblenest to breed bettas, and I'd have to say that yeah, having those bubbles may not work so well. You need a fairly undisturbed surface for the male to build.