You love your pet fish, but constantly neglect them, leaving them to feast on each other's soft cadavers like a Uruguayan rugby team. Instead, integrate them into a mandatory part of your life with Fish n' Flush: a fully-functioning aquarium/toilet tank.
Developed by California-based Aqua One Technologies, the FnF is a filtered acrylic aquarium wrapped around an integrated flush-tank core. The aquarium exists independently of the toilet's reservoir, so you won't annihilate your buddies after every urination. But, to keep things interesting, the flush valve does launch a jet stream into the tank that swirls the fish for a few seconds of exhilirating tidal joy. Wee.
Warning: make sure you have a two-piece toilet and are familiar with basic plumbing, or risk a poo geyser in your bathroom. Once installed, your only additional purchases are freshwater fish and one of those stupid bubbling treasure chests. Then you can unzip, enjoy, and never forget to feed your fish again.