Owning a fish is an exercise in mental fortitude. You might think your little underwater friend will bring tranquility to your life, that you will experience the joy of pet ownership without the commitment or mess.

Wrong. To own a fish is to experience a near-constant anxiety crisis. You will find yourself checking approximately 100 times a day to see if your fish is dead, wondering if it might be happier with a castle or perhaps a plastic pineapple, and realizing that its life in that waterlogged box is both very depressing and a very good reminder of your own mortality. You will find yourself Googling things like, “Fish pacing back and forth in tank” or “Can fish love?” and not feeling at all good about the answers you find.

If you really must get a fish, though, here's some advice: Get a low maintenance tank. Relieve yourself of the stress that comes with cleaning and filtering and fiddling with temperature, allowing yourself to move up Maslow's hierarchy of needs when questioning your fish's happiness. I suggest Back to the Roots, an Oakland startup that makes a compact, self-cleaning aquaponics tank. It provides a nice place to house your fish, with a miniature garden that filters the water and repurposes fish waste as fertilizer.

For the uninitiated, aquaponics refers to systems in which fish and plants enjoy a symbiotic relationship. To oversimplify just a tad: As fish swim around, they eat and poop and their waste gets sucked up by the water pump. The pump delivers water to the garden in the lid, providing nutrients to the plants. The plants, in turn, filter the water, which returns to the tank. Voila! A self-cleaning, self-sustaining ecosystem that requires little maintenance.

Back to the Roots

The practice supposedly goes as far back as the Aztecs, though modern incarnations can be found in places like Bangladesh, Malaysia, and Barbados, where people use aquaponics to boost food production. For us amateurs, though, tabletop systems provide a nice place to put your fish, an easy-to-grow garden, and a tank that demands very little of you.

Aquaponics for Dummies

The Back to the Roots $100 starter kit includes with a 3 gallon tank, a water pump, gravel for the floor of the tank, grow stones for the planter tray, and packets of wheatgrass and radish seeds. The company also throws in fish food and a bottle of beneficial bacteria to kick-start your little ecosystem. Just add water—and fish.