First, we need to understand how a fish digests and absorbs its nutrition. Humans absorb their energy from carbohydrates, considered to be a good energy source. Fish, however absorb their energy from lipids, and so fish need more protein in their diets then, say, gluten. Amino acids also need to be considered in a fish’s diet. All animals have different kinds of amino acids they need to survive, for example, cats need taurine in their diet or they will have heart problems. Some fish digest slowly, the best example are goldfish, these fish cannot handle large quantity of protein in their diets because of slow digestion. These fish should be feed either less or a less meaty food to prevent bloat or dropsy from intestinal gas or infections.
Back to amino acids and proteins, we need to understand that not all sources have the equal nutrition. The amino acids fish need to be healthy are Arginine, Histidine, Isoleucine, Leucine, Lysine, Methionine + Cystine3, Phenylalanine + Tryosine4, Threonine, Tryptophan, and Valine. These are most found in whole fish meal (salmon works best), Cyclops, fish roe, and surprisingly spirulina algae. Some fish foods supplant meaty protein with plant and wheat protein, which is practically filler and lacks the vital lysine and methionine acids. Therefore, depending on the fish, the more meaty protein and the less plant protein the food has, the better the food.
Lipids, or fats, provide a fish with energy, insulation, protection against shock, and promoting healthy cells. Fats also help the fish absorb important vitamins A, D, E, and K. These vitamins are fat soluble, and can only be digested and absorbed with fat. Lipids from whole fish meal contain healthy polyunsaturated fatty acids and omega-3 and omega-6. These fats are needed to promote health in a fish and are important in any fish food. These can only be found in whole fish meal, as plain fish meal is devoid of these healthy fatty oils.
Carbohydrates are found in sugars, starches, gums and celluloses. Most carbohydrates enter fish through plant matter. Due to this, carnivorous fish have little need for them. The plant matter they do absorb is digested from a prey’s stomach contents when the predator consumes them. Feeding carnivorous fish a food high in carbohydrate containing food will leave them with malnutrition. The opposite is that herbivorous fish will gain from foods high in carbohydrates.
Throughout this, I have mentioned fish meal. But what is it? There are two types. If on the ingredients it says “Fish Meal”, then they mean the waste, bones, and offal of fish not suitable for human consumption. In short, it’s the pink slime of fish food. The desirable kind, is “Whole Fish Meal”, which is fish caught purposely to be made into fish meal. It is a whole fish ground up, and still contains all the essential amino acids and protein and lipids. It is even better if it lists a specific fish, such as “Whole Fish Meal (Salmon)” or “South Antarctic Krill”. Whole Fish Meal also contains 17%-25% ash, which contains vital minerals like calcium and phosphorus, which aids in osmoregulation. The only drawback is that whole fish meal is 2 to 3 times more expensive then regular fish meal, but is worth it in the long run.
Shrimp meal is a good ingredient, it contains pigments that help brighten colors and is very tasty to fish and helps to feed finicky fish. It is used as a meaty protein source, but is still inferior to whole fish meal.
Squid meal is a highly digestible protein source, good for feeding to fry to encourage fast growth. It contains plenty of good minerals and vitamins.
Brine shrimp has a good amount of carotene for color amplifying and acts as a natural laxative, but is used sparingly because of its high water content.
Spirulina is found in almost all fish foods, because it contains many healthy compounds. It has raw protein and vitamins A1, B1, B2, B6, B12, C and E. It also contains pigments beta-carotene, which improves coloration. Because it is more of a bacteria then algae, it boosts a fish’s immune system because a fish will release antibodies to investigate.
Garlic is a wonder in any fish food. It is antiseptic, boosts immune system, helps resist parasitic infections, and vigorously induces appetite to finicky fish. Garlic also contains Allicin (Diallyl thiosulfinate) It has been scientifically proven to treat fish tuberculosis. Some human studies show the effectiveness of Garlic in treatment Streptoccocus (which can affect fish).
Beef heart should rarely be used in fish food, and fed only as a treat. Carnivorous fish may enjoy it, and it helps fry grow quickly, but it is 18% saturated fat. It negatively affects the fish’s digestive tract and kidneys, causing a short lifespan. A study in the 1980s had Oscars eat primarily beef heart and the fish had much shorter life spans and were more prone to disease like HITH. The aquatic author Martin A. Moe once stated “Fish are cold blooded and all digestion reactions take place at 70 to 80F, the temp of aquarium water. Thus they may not be able to efficiently digest or use the types of fats present in the flesh of warm blooded animals. They are much better off with the flesh of animals that are similar to their normal prey,”
Soybean meal has been used as a meaty protein substitute for a while. It contains most of the good amino acids, lipids, and vitamins, as well as being cheap. But it still lacks what whole fish meal has. Soybean meal is a better filler than wheat germ, but it should never be listed as the first ingredient.
Wheat Germ is a carbohydrate, and not the best for fish. It’s used as filler for protein, but it still contains vitamin E, good for improving fish color. Wheat Germ is best used in foods for goldfish, as it provides protein but slowly and not as meaty as fish meal. It helps prevent bloat and other intestinal distress commonly found in goldfish.
Fish color enhancers should always be found naturally in their food, such as carotenoids, zeaxanthins, and astaxanthins.
By using these facts, I have taken some of the most popular fish food brands and rated them on a scale of 1-10. 1 being poor, 10 being excellent. I look at the ingredients and check to see what protein source is used, additives, and fillers. I will not take personal experience into my ratings, nor if fish enjoy it. See, fish food is like junk food. If you put candy and spinach in front of a child, they will always go for the candy. Just because a fish likes to eat a certain food, doesn’t make it good for them. The popular excuse “my fish loves it, so it must be healthy!” is as dumb as saying “My kid loves eating Twinkies, so it must be healthy!” Some fish may not take to the healthiest food on this list, and that’s ok. You will need to supplement with other foods or drop some vitamins on before feeding.
Here are some fish foods rated with the facts above:
TetraMin Tropical Flakes- 3
Loaded with fillers, artifical dyes and poor protein sources
Drs. Foster and Smith Tropical Flakes- 7
Good sources of protein, few fillers, natural coloring
Cobalt Aquatics Tropical Flakes- 7
Good sources of protein, garlic, loads of vitamins
Hikari Micro Pellets- 6
Garlic, important amino acids,carbohydrate fillers
O.S.I Freshwater Flakes-5.5
Poor protein source, carbohydrate fillers
Aqueon Tropical Flakes- 8.7
Great protein sources, full of vitamins and amino acids, few fillers
Wardley Advanced Nutritioned Perfect Protein Tropical Flakes-6.5
It's got protein all right...plant matter and filler protein
Sera O-Nip Tablets with Tidbits- 7
Few fillers, but moderate protein
API Tropical Fish Flakes- 9
Great protein sources, garlic, full of good vitamins, amino acids, and great ingredients
New Life Spectrum +Thera-A-10
No fillers, great protein source, garlic galore, nothing artifical
Edited by Crossfire, 19 August 2012 - 11:38 PM.