Few marine fish look as electric as the powder blue tang, and few punish shortcuts as quickly. This fish is active, bold, beautiful, and less forgiving than many beginner favorites. When its tank is too small, unstable, or crowded with the wrong fish, problems can show up fast. A healthy Powder Blue Tang is one of the great showpiece fish in a reef tank. It cruises all day, picks at algae, flashes its bright blue body and yellow dorsal fin, and acts like it owns every inch