Sexing and Color: You can tell the males from the females (sexual dimorphism) fairly easily. Both sexes are an eye-catching iridescent silvery blue. Sometimes you can see a light orange background that appears behind the rows of silver scales. The males sport red top and bottom fins, which they enjoy flaunting at the females. When swimming, they tend to flatten these fins suddenly opening them when they change directions. Females have the same size fins, but they are yellow or orangish yellow.