Containment is Often Confused with Control

 Always with the fish tanks--contained chaos.

And this time I didn't feed them. Ever. 

The big ones started eating the little ones, as fish will do. But when that no longer sufficed, they began to watch the world beyond the tanks with their intelligent eyes.

The yellow cockatiel perched on the lip of the tank, and that was the end of it. Once the red cleared away, I could see the feathers settled on the bottom. 

The blue cockatiel witnessed the bloody event and spent too much time flying around the room, teasing and torturing the starving predators. Swooping in almost, just almost within attacking distance.

He should have known the fish were adaptive. They studied hjm as he circled the rim, and all the while they were learning how to fly.