TFA101

I want my cardinals and black tetras to yield the best colors ever. Is that done in subdued or bright lighting?

Coryd55

Normally brighter lights make fish show more color but the color of substrate and decor and use of plants makes the colors deeper or lighter.

sirdarksol

In part, it has to do with your preferences. Some people prefer the colors yielded by different colored light (even simple differences between wavelengths of normal fluorescent lights). Darker backgrounds and substrates can highlight some colors better, while white backgrounds/substrate can wash the colors.

RiffDawg15

Variety in the fishes diet also helps bring out the best color in them!

nugzboltz

Having fluorescent lighting in the mid temp range (~5000-6500K) should make all the colors more vibrant as that is the whitest, most sunlight-like light.

Incandescents, which are in the lower temp range, tend to cast an orange/red glow on everything, whereas the higher temp range flourescents casts a blue one.