2 Pack of Zoo Med Tropic Sun 5500K Daylight Fluorescent Bulb T8 25 Watt, 36-Inch. A 5500K bulb that is ideal for freshwater fish and live plants. The Tropic Sun is a full spectrum daylight lamp, which simulates natural sunlight for optimum aquarium viewing. Our Tropic Sun daylight bulb brings out the natural beauty of fish and plants and is our most economically priced bulb. Zoo Med's line of fluorescent aquarium lamps are made in Europe for ultra high quality, color, and longer burn life. Our energy saving T8 sizes can save you up to $30.00 per year in electricity over the thicker T12 size lamps! Effective up to 10,000 hours.