Rainbowfish are small to medium-sized freshwater fish from the family Melanotaeniidae, renowned for their vibrant, iridescent colours such as yellow, teal, red, green, and orange. A popular species is the Boeseman’s rainbowfish (Melanotaenia boesemani), distinguished by a blue-grey front and bright orange rear. These fish typically grow up to around 4.7 inches and are loved for their striking appearance.