It has been decided: three fish: two goldfish, and one catfish.

One goldfish looks sad; the other looks happy. The catfish is tiny and ugly, and hovers naturally near the naked bottom of the tank.

The aquarium is otherwise empty, except for a filter to keep the water clean. It's perched on the tank's upper edge and tumbles a small waterfall of filtered water into tank. The water passes first through a thick sponge, and then a pouch of charcoal, before pouring cleanly back into the tank.

I fed the fish but they apparently weren't hungry, or were too shocked by their transplant to partake. The food sunk to the bottom, ignored.