 Page 5 of 11 Lipids - How Much Is Too Much?
Lipids (fats - omega 3&6) are high-energy nutrients that supply approximately twice the energy as proteins and carbohydrates, and typically should comprise approximately 5-10% of tropical fish diets. They also supply essential fatty acids and serve as transporters for fat-soluble vitamins.
Digestibility:
If cost is an issue, and it usually is, then one needs to take a very close look at the overall feed conversion ratio, which most hobbyists fail to do. It always amazes me when I overhear hobbyists comparing fish foods by nothing more than the sticker price. It's simply impossible to do! In some cases, the food that appears to be more expensive is actually the better buy due to it having much higher digestible ingredients.
When a premium high quality food is being used, you just might be surprised at how little food is actually required to keep your fish in optimum health. |
Fatty infiltration of the liver has been designated as being one of the most common metabolic disturbances and frequent cause of death in aquarium fishes. The connection between excessive lipids and fatty liver disease has been common knowledge in the aquaculture industry for many years. The Department of Fisheries and Aquatic Sciences at the University of Florida again recently confirmed this in a study involving African cichlids as test subjects. Yet a recent trend in some fish foods is to use higher levels of lipids in the diet, in order to partially spare protein. Although increasing dietary fat can help reduce the high costs of diets by partially sparing protein in the feed, serious health issues such as excessive fat deposition in the liver are often the end result. In my opinion 5% fat is not enough energy expenditure for any species of fish, therefore in feeds with the aforementioned rate of lipid content the fish will have to tap into the protein source to compensate for some of its energy expenditure. Using this type of formulation, no excess fat is available to be deposited in or around the vital organs such as the liver. Keep in mind that there is a big difference between fat fish, and muscular toned fish. 
Even for the average hobbyist with only one or two aquariums, the savings can be substantial between a high quality easily digested food, and one that has fair to poor digestibility. Many hobbyists might not even notice the difference, but when you start running a few thousand gallons worth of tanks, with most of them being bare bottom tanks, the excessive waste build up from one food to the next becomes quite apparent. Also, the cost difference in total food used can be staggering over the course of a single year, let alone a lifetime of feeding your fish.