Spectrum for Color
Warm white (3000-4000K) enhances reds and oranges. Cool white (6500K) washes out warm tones. Choose based on dominant fish color.
RGB LEDs with adjustable spectrum let you tune for each fish. Some keepers run warm spectrum during feeding and neutral outside that window.
Duration Rule
6-8 hours max per day for a fish-only tank. 10-12 hours only if you have live plants. More hours = algae dominates.
Use a timer — never leave lights on 24/7. Goldfish need darkness to rest; chronic light stress dulls color over months.
Intensity Balance
Goldfish don't need high PAR — they're not corals. A 20-30W LED over a 200L tank is plenty. More wattage just fuels algae.
If algae explodes despite low hours, reduce intensity or add floating plants to block upper-level light.
Color-Holding Feeding Pairs With Lighting
Spirulina-based pellets combined with warm lighting give the deepest reds. Astaxanthin + moderate light gives strong oranges.
Diet without lighting = color shifts but slowly. Light without diet = no color improvement. Both together = fast results.