Banded archerfish colourations, such as yellow, have been observed. Four to six broad black bars may be present on the dorsal side. The first bar is found anterior to the operculum, the bony plate covering the gills, and the second is found behind the operculum. The third bar is found below the origin of the dorsal fin, the fourth bar below the soft dorsal, and the fifth (if any) on the area between the anal fin and caudal fin (caudal peduncle). These bars become shorter as the fish ages. The lateral line curves upwards at the area between the fourth and ninth
Operculum (fish) the shape is visible and then the individual components are developed days later. The size and shape of the operculum bone is dependent on the organism's location. For example, fresh water threespine sticklebacks form a less dense and smaller opercular series in relation to marine threespine sticklebacks. The marine threespine stickleback exhibits a larger and thicker opercular series. This provides evidence that there was an evolutionary change in the operculum bone. The thicker and more dense bone may have been favored due to selective pressures exerted from the threespine stickleback's environment. The development of the operculuar series has changed dramatically