My betta makes the occasional bubble nest but for the most part he just spits random, messy bubbles all over the surface of the water in no particular pattern. Is he just inept or is there a method to his madness? It's kind of gross.
Well, it's June in Virginia, so no shortage of humidity. Altho I did recently replace his solid lid with a mesh one to keep the temperature from rising and that probably reduced the humidity right on the surface.
He did build a little round nest last night and it's still intact this morning. And the bubbles all over the surface don't move either - they are just messy and random and apparently held in place by fish spit.
I always figured my betta was "testing" the water currents in his tank, looking for the perfect spot to build a nest. The filter is baffled, so only part of the tank has a little surface current. He randomly blows bubbles, watches them, and after several seconds, will return to where he blew the bubble as if checking to see if it stayed put. That's my two cents.