Beta-Carotene is the natural substance that will enhance your captive fish and invertebrates' natural color as well as improved their health and vitality. In most fish, beta-carotene is responsible for enhancement of the yellow color (pigment).
Beta-Carotene also can be used as a gut-loading diet supplement. Add 1/8th teaspoon to the gut-loading container and let live brine shrimp or live rotifers feed for at least one hour prior to straining. Then feed to live animals.