Principles of Colour Enhancing Koi Foods-Peter Waddington @ Infiltration Here are some key words to look for when considering dietary supplements that will enhance red pigmentation in your koi - carotenoids, canthaxanthin, astaxanthin, spirulina, Musca Domestica and Krill. Carotenoids are a family of over 600 natural lipid-soluble pigments that are produced within microalgae, phytoplankton, and higher plants. They also produce compounds such as essential fatty acids, steroids, sterols, vitamins A, D, E, and K. Within the various classes of natural pigments, the carotenoids are the most widespread and structurally diverse pigmenting agents. They are responsible, in combination with proteins, for many of the brilliant yellow to red colors in plants and the wide range of blue, green, purple, brown and reddish colors of fish and crustaceans. Carotenoids are absorbed in animal diets - sometimes transformed into other carotenoids, and incorporated into various tissues. As we all know, flamingo's are pink or should be pink - this is due to ingesting algae containing high levels of beta-carotene and then converting this yellow carotenoid into canthaxanthin and astaxanthin before depositing it into the feathers and tissues as red plumage. Some fish species such as koi and various crustaceans have the enzymatic mechanisms to convert carotenoids into other forms as well, such as astaxanthin - some fish/animals don't. Astaxanthin is the optimal carotenoid for the proper pigmentation of the red/pink colors is aquaria. Crustaceans and other aquatic animals are unable to produce astaxanthin de novo (naturally), only plants and protists (bacteria, algae, fungi) are capable of synthesizing carotenoids. Therefore astaxanthin must be available in either their native habitat or manufactured diet to meet nutritional requirements. In the natural aquatic environment, astaxanthin is biosynthesized in the food chain within microalgae or phytoplankton at the primary production level. The microalgae are consumed by zooplankton, insects or crustaceans which accumulate astaxanthin, and in turn are ingested by fish which then accrue astaxanthin. Fish in the wild will obtain natural red, orange and yellow color pigments, via carotenoids, through natural food sources such as shrimps, snails, daphnia and blood worms. Pond's lack these natural food sources so the fish require a supplement to their diets. Unfortunately natural color enhancers are an expensive addition to a diet, so many fish foods do not contain them or they are provided in such small quantities they are not effective. I personally feed a very high protein, low fat, low carbohydrate diet. For pellet food I usually use Hikari Excel, Hikari Hi-Growth, Hikari Wheat Germ . I use a paste food that starts out at 63% protein off the shelf. In that paste food I mix several different ingredients - Musca Domestica (common house fly) either the larvae, or I prefer the pupae as it floats better and is 55% protein. You can also buy Musca Domestica larvae that is 'gut loaded' with canthaxanthin and or spirulina. The spirulina I use is 60% protein with just 7% fiber. Freeze dried Krill which is a small shirmp-like member of the Crustacea family, is up to 70% protein. Krill are planktonic and feed on algae rich zooplankton where they get astaxanthin - up to 80-120 ppm of astaxanthin where your koi, at most, contain 5-8 ppm in their tissues. I like the fact they're freeze dried instead of using heat which can/does destroy some of the vitamins and fatty acids. Here is the breakdown of Musca Domestica pupae: Calories per gram 6.13 Crude Protein 55.5% Amino Acid Profile Aspartic Acid |