A lighting fixture for promoting the development of animals comprises a backlight, such as an LED or an array of LEDs, and a series of one or more retractable, rotatable or interchangeable lenses comprising quantum dots, such that the color and/or color temperature of the light emitted by the lighting fixture can be altered and optimized during animal development. A lighting fixture adapted for use on an aquarium may be in the form factor of a standard fluorescent tube and comprise one or more LEDs and a quantum dot-containing film for down-converting at least a portion of the light emitted by the LEDs so as to provide optimum wavelengths for photosynthesis by aquarium plants while simultaneously providing attractive display lighting for the aquarium fish.