Goldfish especially should not be kept in bowls, and often small to medium tanks are not adequate. They can grow quite large and need companions. 3 gallons is

Goldfish especially should not be kept in bowls, and often small to medium tanks are not adequate. They can grow quite large and need companions. 3 gallons is the minimum size you should keep a beta fish in, but many peoe recommend at least a 5 gallon tank. It's possible to keep beta fish in a tank with certain other fish but I don't know much about it. One of the best things you can do if keeping a freshwater aquarium is to fill it with plants. They help to filter the water, provide oxygen, prevent algae blooms, provide hiding spots for fish, and can even be a food source if done right. Diana Walstad's The Ecology of the Planted Aquarium[1] is an excellent book on this topic. Easy to find a PDF version online. [1] https://www.goodreads.com/book/show/91597.Ecology_of_the_Planted_Aquarium https://www.goodreads.com/book/show/91597.Ecology_of_the_Pla...