How do I make my guppies more colorful

Fresh vegetables like spinach, broccoli and romaine lettuce are also healthy sources of vitamins and minerals that will help your fish to achieve their natural coloration. Be careful when purchasing color-enhancing commercial foods because some foods will be better for your fish than others. Jun 16, 2021 (source)
U.S. scientists say they have discovered why male guppies, the most fertile member of the fish tank, are so colorful. The University of Illinois researchers, working in Trinidad, say the answer is genetic, with the vibrant colors used to attract females. Jun 1, 2006 (source)
https://www.youtube.com/watch?v=B4x8BxAQ_8Q
Some types of guppies have females who are also quite colorful, so you may want to use other physical markers to determine the sex of your guppy in addition to coloring. (source)
https://www.youtube.com/watch?v=U-3q-7ZEVbw
Mixed Seaweed – Seaweed is one of the few foods that enhance the full spectrum of colors, from red to blue, with each species excelling at one color more than others according to the color of the seaweed species itself. For example, green seaweed excels at blue enhancement and red seaweed enhances red coloration. Dec 28, 2013 (source)
Typically, they will begin to get some color when they are between 1 week and 6 weeks old. (source)
While guppy females are camouflaged by an inconspicuous reticulate pattern, guppy males are highly colourful, displaying iridescent, orange, and black spots and stripes. Jan 24, 2014 (source)
These findings were consistent with previous studies that observed that guppies are attracted to the color orange (Rodd et al., 2001). Feb 28, 2013 (source)
Answer 2: Food coloring that is ok for humans to eat, such as many vegetable-based dyes, should not be harmful to fish. However, as with most things in life, too much food coloring would not be so good for fish. It only takes a few drops to change the water color in a 10 gallon tank. Jan 29, 2010 (source)
An interesting fact about seaweed is that the different product colours are known to bring out that colour in fish. For instance, red seaweed brings out the red colouration, blue brings out blue and so on. (source)
Loss of color in fish can be a sign of severe stress. Stress can be brought on by disease, poor water quality, over cleaning the tank (too frequent or too large water changes), over aggressive fish, poor or inadequate nutrition, being moved, over crowding, and a host of other situations. (source)
The rarest Guppy Type would either be a Moscow Guppy or the Dragon Face Guppy. These two are unique in color and in their pattern. (source)
Genes from both parents should be mixed together to form either a male or a female fish. So why only males get these vivid colours? Scientists now say that male guppies have chromosomes that only exchanges genes at their very tips. This means that colours are passed to males only and are inherited almost unchanged. Mar 25, 2019 (source)
In the final stages of pregnancy, this spot will become black and the guppy will look very bloated or fat. Other signs of pregnancy include: The fish’s coloring will fade. (source)