My dwarf blue Gourami, 'Smurf' (he's a blue gourami that lives in a fake tree root ornament LOL) did the same thing a couple of days ago.
Ive got his tank on top of a lovely old set of drawers. I was vacing it and all of a sudden "splat",right next to me.
He was on top of the drawers,looking right at me...as if to say "Hi Dad,what's happening" 😄
I gently placed him back in his tank,he swam to the back of the tank turned and came back to the front and instantly started acting like nothing had happened...He's a staunch little bloke
Like you TG,it's the first time my Gourami has ever decided to do that...it makes me nervous now when i take the lid off his tank.😄