Hormones may be used to enhance fish coloration by causing a false early maturity. Testosterone supplied in the diet likely allows a premature storage and expression of pigments in the chromatophores. Fish that often exhibit drab juvenile coloration may then show full adult coloration. Fish treated with hormones often become all male, sterile, and require a continuous dietary supply of hormones to maintain coloration. The sex of juvenile fish is often ambiguous and hormone diets, most often containing testosterone, create all male fish. Uncontrolled doses of testosterone sterilize fish. Endogenous production of hormones ceases, so coloration is not maintained when fish are taken off the hormone treated feed.