(2 Pack) Of Zoo Med Laboratories AZMHLC15 15-Watt Highlights Incandescent Bulb, Clear. Zoo Med's Highlights incandescent aquarium bulbs are a new addition to our aquatic line of products. The clear bulb provides beautiful color illumination that will not distort the colors of your fish, plants, or tank decorations. The 15-watt aquarium lamp is 5 inches long and 1.5 inches in diameter.