Feeding Myths & Best Practices

FISH FOOD VARIETY

Variety Is The Spice Of Life. It’s a common saying. This leads us to the question: do fish get bored with one food? A common answer is:

“Would you want to eat the same food all the time?”

This attributes human thoughts to your aquarium dwellers. Many marine butterflyfish eat only coral polyps in the wild, and would starve to death rather than switch foods in captivity. Harlequin Shrimp only eat the tube feet of starfish. Outside the world of aquaria, Koalas will die before eating anything other than specific varieties of eucalyptus — and Monarch Butterfly caterpillars only eat milkweed.

Assuming a single food can healthily sustain your aquarium companions, this isn’t an issue. Fish can’t become ‘bored’ with a food.

Thriving on a Single Food: This leads to a question of whether your fish can thrive on a single food. The answer is YES!

One reason a diet of various products is still promoted is that until this past decade or so, most commercial aquarium diets didn’t provide optimum nutrition. This led to a cycle of feeding fish a basket of foods deficient in one way or another in an attempt to “cover the gaps” in the nutrition being provided each.

Fish do require a varied diet. Yet if a single food is made from a wide variety of nutritionally balanced ingredients, in their proper ratios, this “varied diet” can be found in a single formula. If a food contains krill, fish, spirulina, a basket of other algaes and seaweeds, trace elements, minerals, fish oils, beta-carotene, et. all — isn’t it like feeding these foods separately? And if only high quality, premium ingredients are being used, that single food is far healthier for the fish.

This concept is proven in commercial aquaculture — which is responsible for the vast majority of science used by commercial fish food brands when formulating their products for tropical fish.

The information gleaned from these aquaculture studies is basically sound, but a majority of the research is on fish raised for human consumption. Coloration and longevity of the animal isn’t a consideration (with certain exceptions like salmon where the flesh color is important for sales). Formulas for tropical fish must be modified.  Examples are: lowering the amount of lipids (fat) used, utilizing high-quality marine protein, and including a wide variety of natural color-enhancing ingredients such as krill, spirulina and astaxanthin.

 Finally, when evaluating whether varying your fish’s foods is inherently better: imagine a diet where every other day you ate grilled fish, brown rice and a salad — and the alternate days you ate a Fast Food Cheeseburger, Fries and Soda. This is “variety”: but not the good kind. Supplementing your fish’s diet of nutritionally balanced dry foods with several, less nutrient-complete foods is a similar type of dubious “variety”.

LIVE FOODS, FROZEN FOODS & BEEF HEART

Live Food. With many species, there’s a risk of fry mortality due to failure to eat within the first few days. This is why many commercial breeders use foods like baby brine shrimp or micro-worms to get the fry to start eating. Fry fed baby brine shrimp have a more uniform growth rate than those fed commercial dry food. Yet once they pass 2+ weeks, a high-quality dry food can often out-perform live diets.

Most live foods risk introducing pathogens (diseases and parasites) and pollutants to a system. They also aren’t as nutritionally complete and have nutritional drawbacks. Black, White and Tubifex Worms, for example, contain excess fat that can cause deposits around the vital organs.

Frozen Foods. Most commercially prepared frozen foods for aquariums are about 80% water. The very process of freezing foods like Brine Shrimp causes the cell membranes to rupture. When this food is thawed and rinsed, much of the nutrient will leach from the animal and what is left is mainly shell with little nutritional value.

Both live and frozen foods have their place in an aquarium diet. The reality is that there are some fish that simply will not eat dry food. In these cases, hobbyists have no choice but offering frozen or live food to entice fish to eat as soon as possible, with the hope of eventually training the fish to eat the more nutritionally sound dry formulas.

Beef Heart. This aquarium diet is worth a special mention due to its popularity with Discus breeders (allowing their fry to grow-out rapidly and conditioning their breeders for egg production).

It works for these purposes. It also might account for the short life expectancy of many Discus. This food has the highest water pollution potential. Many Discus breeders in Asia change their water as much as 2-3 times daily to maintain water quality in their grow-out tanks!

Discus can sometimes be resistant to pelletized food because they’ve been raised on beef heart. Yet with some effort, even Discus can be trained to accept the cleaner and nutritionally balanced dry food.

The Dangers of “Yo-Yo” Feeding. Diets of live and frozen foods do work to an extent, and have since the advent of fish breeding. However, for much of this time commercial, nutritionally formulated fish foods weren’t available.

Commercial diets have come a long way in recent years, and are better at ensuring that your fish are provided with what they need for optimum growth, long-term health, color and vitality. Frozen and live foods work on short-term basis. However, continually “supplementing” your fish’s diet with these so-called “treats” can have an undesirable consequence. Due to the palatability of these types of food, fish will often prefer them to the balanced dry foods — making them more likely to reject the healthier diet. We call this “yo-yo feeding”.

There’s always a temptation to indulge your aquarium companions. But this is like giving kids a choice between veggies and a piece of chocolate cake. The cake tastes good, but isn’t good for them.

FLAKES VS. PELLETS

Any discussion of fish food must include a brief comparison of the two main types of commercially formulated foods: pellets and flakes. Flakes have been the most popular form of food among hobbyists for over 50 years. However, commercial operations learned long ago that pellets are a far superior choice for feeding applications.

Pellets boast a few key advantages over flakes: nutrient density, water stability and nutrient integrity.

Pellets are much more nutrient dense, and thus are the optimum method of providing nutrition to your fish. This is particularly true for species of fish over 2-3 inches. This means you can feed much less volume of pellets to achieve the same results versus flakes.

Not only can you feed less, but those pellets you introduce to the tank will remain stable in the aquarium for an extended time. By their very design, flake foods are paper-thin. This leads them to absorb water quickly. Because water can flow into, saturate, and flow out of these thin flakes quickly, water-soluble vitamins leach into the water in a very short time. Some studies suggest that once flakes are added to an aquarium, the majority of water-soluble vitamins (like vitamin C) are leached out of the flake food with 60-90 seconds. As a bonus, not only are pellets better for your fish, but P pelletized food costs less per ounce.

This has been common knowledge in aquaculture circles for decades, but inertia within the hobby has led to insistence on using this outdated and suboptimal form of feed. Yet the use of pellets has been proven in aquaculture since it’s modern inception.