I suggest you use colored paper, to see how various colors look. Your 'best' will depend on your lights, substrate, pants/fish/inverts and room lighting.
Here's a ligt blue painted background I did with left over interior flat wall paint. coats 1-3 were white with the lightest of blue tint. Coats 4-5 were flat white.
I used 5 very thin coats to avoid brush marks.
Lighter colors will reflect light, black will absorb it. So keep that in mind to get the affect you are after.