Why are guppies so colorful?

U.S. scientists say they have discovered why male guppies, the most fertile member of the fish tank, are so colorful. read more

Fancy Guppies are colorful specially the males and to some extent some strains for the females. Fantails and the like are a product of human intervention, careful selection of wild caught guppie which are very colorful but have shorter pointed tails. read more

So it's a fine line, too bright, you get eaten, too dull you dont get to mate. Also wild guppies are no where near as bright as fancy ones. The fancy ones have been selectively bred over generations to have the brightest colours. read more