Choosing a fiber optic color is a personal preference. I will analyze the pros and cons that will help in choosing the right fiber optic color.  Fiber optic sights are great for  everyday carry or home defense handgun sights. It’s good when shooting in low light but will not glow at night. Personally I will recommend to go  for green or yellow sights. Green and yellow fiber optic sights have advantages over red that go beyond preference. Red is the most popular fiber optic sights but first to switch off when there is not enough light. Eyes are the least sensitive to red.

Human eye has the highest sensitivity around 550 nm i.e. yellow-green light
Red is at the infrared end of the visible color spectrum.

The prismatic color separation is:

Red
Orange
Yellow
Green
Blue
Violet

Note: The most visible colors are in the middle of the spectrum “yellow and green“.  That is why yellow or green is best suited to dusk

Color Frequency (THz) / Wavelength (nm)
Red 400-484 / 620-750
Orange 484-508 / 590-620
Yellow 508-526 / 570-590
Green 526-606 / 495-570
Blue 606-668 / 450-495
Violet 668-789 / 380-450