Get yourself a UVB lightbulb (generally used in the reptile-keeping hobby) that emits visible light, UVA, and UVB. This is the best artificial way of mimicking sunlight. Just like how sunlight gives us a tan, they enhance and deepen coloration on all fish. Don't believe all the fears online of how UV light will harm the fish. Do your research with actual scientific research publications rather than online hear-say and BS, zero harm as the glass/plastic you use that separates the bulb from the water AND the water itself absorbs most of the UVB leaving just enough for natural "tanning" of the fish like in nature with the sun. UVC light waves are the dangerous kind that is harmful to all life (used in aquarium water UV sterilizers that many people use).
Keep in mind most aquarium lighting, even those for reef/coral, don't emit much if any UVB light. UVB light is the primary source of "strong" enough light to stimulate the pigment cells.
They don't just make fish colors look better, the actual color pigment cells in the fish scales/skin actually deepen. This technique is already very prevalent with koi and arowana, I don't know why it hasn't spread to all other corners of the aquarium hobby. You can leave it on for as long as you would typically leave on any kind of aquarium lighting.
Keep in mind most aquarium lighting, even those for reef/coral, don't emit much if any UVB light. UVB light is the primary source of "strong" enough light to stimulate the pigment cells.
They don't just make fish colors look better, the actual color pigment cells in the fish scales/skin actually deepen. This technique is already very prevalent with koi and arowana, I don't know why it hasn't spread to all other corners of the aquarium hobby. You can leave it on for as long as you would typically leave on any kind of aquarium lighting.
