In the bygone era when human beings began keeping fish indoors, they had to use bowls, they had nothing else to keep them in, nor the technology available to MAKE anything different. Today, with the extremely broad range of aquariums kits available today, these neanderthalic relics should be abolished. For goldfish, no fish should EVER be kept in less than 10 gallons (with very strong filtration) per fish. For bettas, the ideal is 5 gallons per fish, but they can get by in a 2.5 filtered aquarium. Fishbowls provide severely limited swimming space, they are not adequately filterable, the amount of water in the tank would be fatally fouled by a goldfish's waste in as little as 3 days without cleaning, for a betta, more like 2 weeks, but the animals still suffer. there is almost no possibility for the goldfish to grow to it's full adult length and would be painfully stunted. Just because fish are cheap and they are not warmblooded and can't make noises does not mean they can be abused like they are! If a person stuffed a labrador puppy into a rabbit cage and kept it there it's entire life, the person would be arrested right away for animal cruelty. in a bowl, Goldfish are lucky to live 2 months, which is what earned them their "die easy replaced easy" reputation. In a proper 10g (preferably larger) they can live 20 years! Bettas can live 2 years in a bowl, but scientists have seen bettas who were kept in 5g filtered tanks lived up to 14 years!!!!!! Love your finned friends, don't stuff them into tiny bowls!