Tetras are one of the most popular and diverse types of freshwater aquarium fish. With more than 150 unique types of tetra fish of varying colors, shapes, and sizes, they make a great addition to any ...

Their fins are translucent and colorful, with shades of yellow, red and bright blue. Male specimens ranged in length from about 1.47 inches to 1.87 inches, researchers said.

Blue lingcod: Though usually white-hued like halibut or cod, lingcod, a West Coast bottom-dwelling species, occasionally looks as though it's been marinated overnight in a tray of Blue No. 2 food dye.

Scientists have discovered more than 180 species of biofluorescent fish that glow in neon shades of blue, red, orange and green -- most of them hiding out in tropical coral reefs.