Fish are a type of animal that can survive in water environments without oxygen, as long as they have access to enough food and space. Some species of fish, including the betta fish, goldfish, and guppies are particularly well-suited for living in bowls without oxygen. These small and hardy creatures have evolved to be able to thrive with minimal amounts of space or resources available. They require very little maintenance compared to other types of aquatic life and can live happily in their bowl homes for years at a time! Betta fish can even breathe air from the surface if necessary. Guppies also do well in smaller tank spaces since their bodies don’t take up much room – but make sure there is plenty of vegetation present so they feel safe while swimming around! Goldfish may need more space than betta fish or guppies due to their size, but they still make excellent candidates for living in bowls with no additional aeration needed. With proper care such as regular water changes and adequate feeding schedules these varieties will keep your tanks clean and healthy while adding beautiful colors and movement to any home décor!