Marineland Compact Flo Bulb 13 Watt (5,500 K) Bulb promotes aquatic plant growth and enhances fish colors, It is a 5,500 K daylight lamp with a 10,000 hour life, It fits all 13 Watt aquarium light fixtures, Replacement Fluorescent Bulb for Aquarium Light Fixtures, SKU: RYLHC3350