It is widely accepted that cyprinid fishes have not more than three rows of teeth developed on each pharyngeal jaw. In this study we describe the East African cyprinid Rastrineobola argentea, with typically four rows of pharyngeal teeth developed on the pharyngeal jaw, a unique feature for the Cyprinidae. Generally the fourth row of Rastrineobola argentea is formed by one tooth, less commonly by two teeth. In a few specimens a fifth arbitrary tooth row occurs asymmetrically either on the left or on the right half of the pharyngeal jaw.