well, I'm a beginner. I have had a male betta in a 5lt jar for 2 months and added an opaline/blue gourami to it, of almost the same size.
The same day, the gourami suddenly was super swift, swam around like a maniac, spurted out immense bubbles, dug into the betta's well-established nest. While doing this, it would fall towards the bottom upside down and then get back to life with a repeat action (of the above). We loved these stunts. All this while, the betta would stay to a corner on the surface. And then the gourami lay between the pebbles. After say about 5 minutes, I tried moving (I could only think that it was asleep) but it had passed out. And my betta was relatively more active after the other was removed.
SOS SIS, NOON, SWIMS
Wicked Twister does NOT go upside down. It JUST SPINS YOU AND you down
As long as it is in all capitals, the word "SWIMS" can be read upside down.
Otto, NOON, SWIMS
That means its dead