The Care of One-Gallon Fish Bowls

Most expert aquarists recommend against the use of 1-gallon fish bowls. In fact, in some jurisdictions, animal-welfare laws actually prohibit their use. One-gallon fish bowls are difficult to stock and maintain, but their compact size and versatility make them a popular addition to dorms, small apartments and children's bedrooms. When space limitations or other considerations impair an aquarist's ability to keep a larger tank, carefully maintained 1-gallon fish bowls can be a viable alternative.

  1. Stocking Guidelines

    • The image of a goldfish in a bowl is pervasive, but in reality, goldfish cannot survive in anything less than a 20-gallon filtered aquarium. The only commonly available fish species that can thrive in a 1-gallon fish bowl is the Siamese fighting fish, more commonly known as the betta. These anabantids are equipped with a lunglike organ that enables them to survive in poor-quality water by breathing air. The dwarf gourami also has a labyrinth organ that enables it to survive in small, polluted bowls. Other options include hardy invertebrates like mystery snails and ghost shrimp. Do not keep more than one individual of any fish species in a single 1-gallon bowl; this will quickly lead to the fishes' premature death from pollution or fighting.

    Planting

    • Live plants offer far more than decoration for a 1-gallon fish bowl. Because fish bowls lack filtration systems, live plants are essential for reducing nitrate, nitrite, ammonia and other pollutants from the water. They also help to increase dissolved oxygen in a fish bowl, which is essential for the survival of fish and invertebrates. Good choices for a 1-gallon fish bowl include Amazon sword, Java fern and umbrella fern. Plant the roots in 1/4 inch of cultured, biologically active gravel. Light the 1-gallon bowl using a compact fluorescent lightbulb; this provides an ideal color-spectrum for the growth of benthic plants. Natural light and incandescent bulbs encourage algae growth.

    Maintenance

    • Unlike large, filtered aquariums, which tend to maintain biological equilibrium with little maintenance, fish bowls require careful attention to water parameters. Test nitrate and ammonia levels at least weekly and provide 50 percent water changes weekly. If nitrate levels spike above 25 ppm or test strips reveal the presence of ammonia, begin performing 25 percent water changes three times per week. If the water is cloudy, malodorous or severely polluted with nitrates (50 ppm or more), a complete water change may be necessary. To avoid the buildup of nitrates, ammonia and other waste products, feed your fish sparingly and institute a one-day-per-week fast. Keep the bowl in a heated room that does not experience severe temperature fluctuations, as these can stress the fish and plants.