Article Index
Basic Fish Nutrition
Understanding Labels
Are Fish Omnivorous?
Protein-The Building Blocks
Lipids-How Much Is Too Much
Preservatives and Why They Are Necessary
Spirulina and Vegetable Matter
What Constitutes a Superior Fish Food?
Bibliography and Recommended Reading

Understanding Labels:

This subject seems to cause a great amount of confusion, so much so that I felt the need to address it in this article. For the most part the fish food industry is self regulated, basically meaning that it is very easy to manipulate an ingredient list to favor your own product. As an example, if the ash content is quite high in the food, the easiest way for a manufacturer to address that issue is to simply not list the ash content on their label.

Ash can come from bones, shells, and scales of marine animals that are high in calcium and phosphorous; to an extent its presence is simply unavoidable. But, the ash from minerals that come from raw ingredients such as Kelp and Spirulina, though beneficial, should be limited. If an excessive amount is used it can have a negative effect, since fish can assimilate only so much mineral content, and any excess will simply be adding unwanted pollution to the aquarium water.

A manufacturer can also use very little of a common raw ingredient such as spirulina, but use green dye to color the food, and promote it as spirulina food designed for herbivores. If you read the label closely, in some cases you may find that the food that was designed for herbivores may in fact be based on generic fish meal and contain very little spirulina or vegetable matter, but instead is loaded with fillers such as corn, bran, middling, flour, potato, etc.

A manufacturer can list Lobster and Crab in their ingredients to signify quality, but in reality it is nothing but the leftover parts of the animals. A manufacturer can also choose to list many species of fish, one species after another, which gives the illusion that the binding agents (such as middling and flour) are several ingredients down on the ingredient list. The fact is that no matter how many types of fish make up the main ingredient, they are still just part of a single fish meal, period. As an example, if one used 500 lbs. of fish meal per ton of food, it doesn't matter how many species of fishes you use to get that 500 lbs., in the end it's still 500 lbs. of fish meal, and the true second or third ingredient will usually be a binding agent such as flour. Many unaware hobbyists see several kinds of fishes listed at the top of the ingredient list, followed by wheat flour, and assume that this particular brand must have very little wheat flour, and a very high concentration of fish protein. In reality it is no more than a single generic fish meal being used, comprised from numerous species of fish. All fish foods require a high quality binding agent, or they would simply fall apart long before they reached the aquarium. Premium foods use as little as 25% binding agent, while lower quality foods can be as high as 50% of middling and flour.

There can also be an extreme range in the utilization of nutrients and overall digestibility within any ingredient category. Shrimp meal is typically comprised of heads and shells, and many fish meals are typically made up from the processing waste of the fish, not the whole fish. Needless to say, a high quality food uses only whole fish, Krill, Mussel, etc., not leftover waste from processing plants.

"The Proof of the Pudding is in the Eating"

Is it possible that one of the main reasons that a varied diet has been promoted for all these years is simply due to the fact that until this past decade most commercial pet foods simply did not provide optimum nutrition? Or do politics and profit play some roles in this long held philosophy?

Most magazines and periodicals are geared towards promoting fish keeping, and assisting hobbyists, but because of the need for sponsorship funds from manufacturers to support these types of publications, they simply cannot publish any comparative fish food studies.

Many hobbyists appear to want to see a controlled feed trial study performed on the top commercial foods. These types of studies have been done. In 2002, an in-depth feed trial study on 33 of the top fish food brands on the market was performed by a group of highly accredited veterinarians based in Singapore. Again, in February 2007, Sparsholt College in the United Kingdom completed a feed trial on Lake Malawi cichlids but the results from both of these feed trials will unlikely be made public due to the politics involved. I believe that the true key is for each hobbyist to perform his or her own feed trials and experiments—as flawed as these experiments may be. It is the only way you will find out and share your findings with other hobbyists to promote the long neglected subject of fish nutrition. Draw your own conclusion, instead of regurgitating what the manufacturers claim. Don’t we owe it to our fish to provide them with long-term optimal health?

In 1996, I published the Marine Aquarium Companion, and at that time I considered species such as the Moorish Idol to be "doomed" when kept in captivity, due to their specialized diet in the wild. At the time that I wrote that book I felt that this species simply could not be kept long term in an aquarium, as no commercial food at that time could sustain some of the more delicate marine species long term. What was once considered almost impossible has now become possible. At the time I also considered the Moorish Idol to be a peaceful species, but I soon discovered every fish is peaceful when it is on its deathbed! A healthy and thriving Moorish Idol is actually quite aggressive, but one will only see this behaviour if the fish is truly thriving, and not just surviving.