danio Syllabification: (dan·i·o)Pronunciation: /ˈdanēˌō/Definition of danio noun (plural danios) a small, typically brightly colored freshwater fish native to South and Southeast Asia. Genera Danio and Brachydanio, family Cyprinidae: several species Origin:modern Latin (genus name)danio in other Oxford dictionaries Definition of danio in the British & World English dictionary