Opalo: "Bettas rarely bubblenest, you say? Hang on, I'll prove you wrong. I'm going to go make one 10 times bigger than I am."
"And that thing about bettas being inactive? Yeah, no, not true. I'm proud of my large home. And don't you dare bother my bubblenests."
Saw someone mention that their betta goes against the filter intake. Opalo does that too. I have it blocked safely with filter sponge, so there's just a tiny bit of suction. He likes to swim very slowly next to it until it sucks in his fins, then he dashes away really quickly. Silly little fish.