Frozen Food For Your Marine Tank

For many reefkeepers frozen foods are the staple nutrition for feeding the captive reef but, given the number of frozen foods available, how do you choose?

Not all frozen foods can be considered equal. To compare what you’re purchasing you need to take into account a number of factors including: price, how the food’s been handled, nutritional value, potential pathogen content, water content, and integrity, not to mention added extras such as levels of antioxidants and colourants.

Price.

To my mind this is one of the least important factors in choosing which brand of frozen food to buy.
Firstly I fail to see what the point is in building up a beautiful reef, investing significant amounts of time and money in the process only to resort to feeding the cheapest – read inferior – foods available in some misguided attempt at economy.
Secondly, if a food is cheap, it’s cheap for a reason. I’m a strong believer that when it comes to price you get what you pay for.

Handling.

Quality foods are flash frozen on collection Compare this with the cheaper foods that arrive at the manufacturer’s premises in bulk as large frozen slabs that are then thawed out for repackaging by the simple expedient of using a fire hose!

Nutritional Value.

Have a look at the information on the food’s packaging; you’ll find little giveaways to quality here by observing what levels of protein are present – heck! I’m amazed at the fact that some manufacturers can actually bring down protein to such low levels, 5% or less, especially considering the protein content that the repackaged animals originally contained … Oh, and they then display this value as though it’s something to be proud of!

Just check out the protein content of our favourite, P. E. Mysis – 69.5%!

Potential Pathogen Content.

Has the manufacture screened their product for bacterial contamination? This is a process that will cost the manufacturer additional money, something to bear in mind in connection with low cost products. The best manufactures carry out testing to ensure their product is pathogen free.
(See Coral magazine Vol. 3 nos.4 and 5 for more on the subject of pathogens present in food)
Other manufacturers may utilise irradiation to ensure a pathogen free product but this may be bring with it other potential problems, not to mention the known nutrient losses from irradiation effecting vitamins A, B1, C, and E.

Any toxins produced by micro-organisms prior to irradiation will remain unaffected and still have the potential to adversely affect any animals that ingest food where they’re present. In the hands of an unscrupulous manufacturer (or one just trying to make an extra buck) irradiation could be used to disguise spoiled food. As irradiation leaves no visible presence, a food with high bacterial load can be rendered more or less sterile, yet it could still pose a hazard as the process kills the bacteria that cause spoiled foods to smell or look bad, leaving us with none of the usual indicators of inedible food.

Water Content.

What exactly are you spending your money on why you purchase frozen food? The chances are, especially with cheaper foods, that you are buying some very expensive water! So although a food might appear inexpensive, in reality you may actually be paying more for the small amount of usable food in the pack than if you were buying a quality food at a higher pack price.
(See the article in Coral vol.1 no. 1, where Daniel Knop suggested defrosting the same volume, of a number of different frozen foods, to appraise what you get for your money)

Quality foods such as P. E. Mysis and Cyclop-Eeze FreezerBar are great examples of foods where you’re not wasting your money by buying water.

Integrity.

When I use the term integrity in connection with frozen food I’m using it as a measure of how intact the frozen organism remains. This is something to be concerned at for a couple of reasons.
Animals that hunt by sight, in particular seahorses, track their prey visually before ingesting it. These animals need to be reassured that the item in question is actually a tasty food item, so a frozen item that remains intact with antennae, legs and eyes still attached where they should be, will be more readily taken – this can be something of a life or death issue with some of the more picky eaters our there.

This is one of the factors making P. E. Mysis the food of choice for American seahorse keepers.

I consider it important to stick with frozen foods that retain integrity when feeding in a reef. When feeding a frozen food, usually crustacean based, if the carapace remains unbroken there is little risk of polluting the tank, any item that’s missed at feeding time will remain inert until something comes along to eat it (usually not that long in a decent reef). Contrast this with foods that are all broken up, they leach nutrients into the water as soon as they enter the tank and anything remaining uneaten at feeding time will be a source of pollution until it’s eventually devoured.

Note! When feeding, you want all the nutrients to remain encapsulated within the food item so that they go where they’re needed – into your reef animal’s gut – and not into the water, where the phosphates and nitrates will be available to fuel all those pest algae and bio films that we don’t want!

Lipids, Antioxidants, and Colourants.

These are a few of the little extras you get in the better foods. Depending on what food you’re feeding, certain organisms can deliver higher or lower levels of lipids or differing percentages of the various fatty acids such as DHA (Docosahexaenoic acid) and EPA (Eicosapentaenoic acid).

Omega-3 fatty acids are a source of lipids; these are compounds that provide twice the energy of protein on a weight for weight basis. If you’ve ever read the label on the fish food you buy you may have come across references to HUFAs (highly unsaturated fatty acids), well that’s what omega-3 fatty acids are. They are the most important source of lipids for marine fishes, but due to the difficulty of processing these compounds they are often deficient in dry foods.

Carotenoids are pigments that give colour to animals and plants, but unlike plants animals can’t manufacture them and must obtain them from their diet. These carotenoid pigments come in a number of forms; for example the main ones in Cyclop-eeze are astaxanthin, a pink pigment, and canthaxanthin, a red pigment, so increased colouration is most likely to be seen in animals that naturally express these colours. But there is more to astaxanthin than colour. Over the last few years, research has shown that it has an important role to play in growth rates, respiration, protection from UV radiation, tolerance to stress, and may help boost the immune system.

Frozen Foods Hints and Tips.

Keep your frozen food in a sealed container to avoid it drying out (freezer burn) or oxidising; this will also prevent unpleasantness when other family members discover what you keep in the freezer!

Avoid frozen foods being repeatedly frozen then thawed. This will rupture the cell structure allowing nutrients to leak out into the water. This applies to our frozen Aquaculture Grade Phytoplankton as well as the more usual frozen foods.

Don’t buy single packs or small quantities of frozen food via the internet. It’s virtually impossible to expect small quantities, especially single packs, to survive posting without thawing. This is why Midland Reefs doesn’t sell any frozen foods unless they’re bought in bulk.
Support your local retailer by purchasing your frozen food from them.

Most frozen products will have “best by” or “use by” dates, pay attention to these and never buy out of date food.

It’s a false economy to buy larger packs of food just ‘cos it’s cheaper in bulk. As soon as you open a pack of food it will start deteriorating, certain vitamins will start to break down resulting in food of poor nutritional quality. Only buy the amount of food your animals will go through in a reasonable time.

Although many of us may mix together a number of different foods in a quantity of tank water to enable us to feed the reef, corals, and fishes all in one operation, don’t leave this mixture for any length of time before using. When feeding using this method, just allow enough time for the frozen food to become defrosted then use the mixture straight a way. Any defrosted food mixture will quickly become contaminated by bacteria from the environment, which will rapidly multiply, the longer the food is left unused.

And lastly, if you take your entire pack of frozen food out and carry it over to your aquarium at feeding time – Don’t forget to put it back in the freezer!!!

Tim Hayes
Midland Reefs
©2007