Will my Common Goldfish get along with a male Crowntail Beta?
First, a 10 gallon is the bare minimum for one goldfish, and in my opinion cruel — get a 20 -28 gallon and a second goldfish, and they will live 20 plus years and become gorgeous and adorable. Goldfish do better with other goldfish, and can only go with other goldfish, but your tank is too small for two goldfish, unless you upgrade in six months to a year as they grow. Bettas definitely don’t go with goldfish — they are warm water fish and have totally different needs. Plus, they will only grow to a fraction of the size a goldfish grows. PS, I keep my betta in a 10 gallon and he thrives, don’t listen to that bunk about keeping them in tiny bowls. I will never understand why people believe meat market type petstores who are trying to sell their wares. Bettas only live in ponds during part of the year in the wild, and they can still jump to different ponds, etc., nothing should be in less than a 5 gallon unless you think it’s OK for yourself to live your entire life in a bathroom. And
