It’s safe to say that every aquarist has heard of colour-enhancing foods and likely used them. The reason is simple: in fish, their appearance, especially their colouration, is the first thing that catches the eye of anyone observing the aquarium. However, it’s important to remember that fish colouration depends on many factors, including genetics, environmental conditions, age, health, and diet. Therefore, by using colour-enhancing foods, we can influence the intensity of a fish’s colouration to some extent. But have you ever wondered how these foods actually work, what they contain, and how they affect a fish’s overall condition?

What do colour-enhancing foods for fish contain?

Carotenoids are the key ingredients in commercial fish foods, as well as in natural live and frozen foods, that intensify fish colouration. They are a group of natural pigments comprising around 1,100 identified compounds with highly diverse structures. Carotenoids are widely distributed in nature across both the plant and animal kingdoms.

Among carotenoids, we distinguish between carotenes, whose molecules consist only of carbon and hydrogen, and xanthophylls, which also contain oxygen. These compounds are fat-soluble. That’s why they are found in the body embedded in cell membranes, dissolved in fat droplets, or bound to proteins in the photosynthetic system. Only plants and certain species of fungi and bacteria are capable of producing them. Therefore, animals, including fish, must obtain carotenoids from their food. I deliberately use the word must because carotenoids perform many important functions in the fish’s body, making them an essential component of the diet.

What is the source of carotenoids for fish?

The primary sources of carotenoids for fish are algae and crustaceans. However, only algae synthesise carotenoids independently. Crustaceans accumulate carotenoids in their tissues by feeding on algae or other organisms that have consumed algae. Interestingly, many fish and crustaceans have special enzymes that allow them to modify the carotenoids they obtain from food. Goldfish and carp, for example, can convert zeaxanthin into astaxanthin.

What carotenoids are used in aquarium fish foods?

Astaxanthin is the most commonly used carotenoid in fish food. One might ask why. Astaxanthin is naturally present in large amounts in wild fish and crustaceans, and it is highly bioavailable from food. Beta-carotene is also widely used due to its good bioavailability.

How much carotenoids should colour-enhancing fish food contain?

Due to the raw materials used, carotenoids are always present in Tropical’s ready-made foods. However, only foods with a high carotenoid content can be classified as colour-enhancing. So, what constitutes a high carotenoid content? Colour-enhancing foods for ornamental fish authorised for sale in the EU may contain up to 100mg of pure astaxanthin per kilogram of product. This is a significant dose that can visibly intensify fish colouration within a short period, often after just two weeks of use.

In addition to astaxanthin, Tropical’s colour-enhancing foods also include raw materials rich in carotenoids, such as krill, shrimp, calanus, spirulina, Haematococcus pluvialis, chlorella, red pepper, and Mexican marigold. These ingredients significantly increase the total carotenoid content in the food.

Scientific studies show that improved colouration in tetras, cichlids, gouramis, goldfish, and danios has been observed at astaxanthin levels of 30 mg/kg in feed. In clownfish, a diet containing 100 mg/kg of astaxanthin intensified colouration after just one week of use. Simultaneously, more intensive growth in the fish was also noted. The recommended doses for food fish range from 50 to 100 mg/kg.

What colour-enhancing foods should you choose for your fish?

Wondering which colour-enhancing food to choose for your fish? Start by checking the astaxanthin content and the presence of raw materials rich in carotenoids. You’ll find this information in the product composition listed on our website. Then, choose the appropriate form – flakes, granules, tablets, etc. and size.

Pay special attention to our unique Tropical’s Colour Booster formula, featured in Tropical Insect Menu Colour. This innovative blend of ingredients is rich in natural carotenoids and works to intensify fish colouration in a short amount of time. The high concentration of various carotenoids addresses the different needs fish have regarding carotenoid type, bioavailability, and the chemical transformations these compounds undergo in the body.

Colour-enhancing foods for fish