The next morning the puffer floated at the tank top dead. We figured he did not adjust.
The next morning it was the swordtail. He too apparently did not adjust.
The NEXT morning, the goldfish floated at the top of water, with a big hunk taken out of him. Murder!
The suspects were the Angelfish and the brown fish. Whichever of these survived the 4th night would surely be the murderer. So, we watched, but nothing happened.
Until the next morning, when the Angelfish floated at the top of the tank.
IT WAS THE BROWN FISH!
My uncle’s friend at the time, Ron, who had taken an interest in our fishtank project (he may have in fact inspired it, as my mother as rule took many ideas from my uncle’s rollicking set), Ron, something of a pet fish afichionado, came over that weekend to see how things were progressing, and, seeing the brownfish, said “You have a Jack Dempsey! That’s a very aggressive terroritoiral fish, almost like piranha!” He correctly identified it and explained it was the obvious murderer of all the other fish. “Oh yeah that guy ate ’em” he said, “he’d eat anything you put in that tank.”
For many years, that Jack Dempsey lived alone & angry in that tank, save for the suckerfish, who was a bottomfeeder, and for some reason, not tempting as a target (or unpalatable) for ol’ Jack. Many years later, he died, and we were kinda relieved, and set aside the fish tank project permanently.