Controlling water quality and successfully introducing livestock into an aquarium are only two of the many important challenges that an aquarist has to face. Feeding the fish and invertebrates with proper nutrition is one of the other ones. Proper nutrition is essential for healthy aquarium inhabitants. Achieving good nutrition is more than choosing a food and feeding your fish. When selecting food for your fish, consider the dietary needs of your fish, as well as the location your fish prefer to feed in the aquarium.
Successful feeding does not only consist of providing suitable foods, but also, in some cases, actually teaching the fish to recognise and eat the food.
Understand your fish's dietary needs.
Fish are carnivores, herbivores, or omnivores. Carnivores are meat eaters and rely on a protein-heavy diet. Herbivores are plant eaters with digestive systems designed to extract nutrients from plant and algae. Most aquarium fish are omnivores and require a diet that includes both meat and plants. Since plant-eating fish are not able to properly digest animal-based foods and strictly carnivorous fish cannot obtain the proper nutrients from a plant-only diet, it is critical to match the food to the dietary needs of your aquarium fish.
Marine fish have a high metabolic rate which requires a constant source of energy. In nature, many fish are adapted, both physiologically and ecologically, to consume certain types of food. In fact, many species (but not the predators) spend most of their time foraging for food. The constant supply of proper foods is needed to provide the energy the fish require for immediate use, growth, resistance to disease, and so on.
The proportion of proteins, fats, carbohydrates, vitamins and minerals that each type requires, differs. Carnivores for example, require a high-protein diet which can be supplied by flesh-based items such as beef heart, fish meat, shrimps, scallops, and the like.
Herbivores on the other hand, require higher quantities of carbohydrates provided by vegetable foods like chopped spinach, lettuce and algae. Micro and macro algae should therefore be promoted in aquariums accommodating herbivore species by the use of algae fertilisers and appropriate lighting. Omnivores require both animal and vegetable matter in their diet, so no single food contains or provides all the essentials. In these cases, a varied diet will ensure that no vital requirement is overlooked.
Fish also need vitamins for health just like any other animal. An improper or incomplete diet can result in nutrient and vitamin deficiencies and the onset of serious conditions such as stunted or improper growth, a weakened immune system, or death. Vitamin supplements, along with a varied diet, are an ideal way to fill in nutritional gaps. Vitamins your fish need:
Vitamin A - from spinach, algae, and crustaceans. It is necessary for normal growth and development as well as for proper formation of bones and scales.
Vitamin B-complex - from spinach, algae, eggs, and fish. It is necessary for normal function of the nervous system, protection of the slime coat, digestion of protein and normal growth.
Vitamin C - from spinach, algae, and fish eggs. It is necessary for disease prevention, healing, as well as normal development of the skeleton.
Vitamin D - from snails and shrimps. It is provides the necessary calcium and phosphorous which helps in normal development of bones and scales.
Vitamin k - from spinach and liver, which helps in blood coagulation.
Invertebrates require special provision for their demands. Generally speaking, invertebrates do not require feeding as frequently as fish do. Anemones, for example, will usually be fine being fed every two days. Crabs and shrimps, however, require more frequent regular-interval feeding, always taking care, of course, NOT TO OVERFEED.
Filter feeders may well be able to obtain all their requirements from the particulate matter suspended in the water in well-balanced aquariums (but check regularly), while those invertebrates which contain symbiotic zooxanthellae (single-celled algae) within their tissues will also need adequate lighting to enable the zooxanthellae to photosynthesise.
There are many types of commercially prepared foods available either as staple diet, or as one of the other various specialist foods, e.g. conditioning, carnivore or vegetable flake, will be found acceptable by many fish and invertebrates.
There are many types of dry and deep-frozen foods available commercially. We use and recommend Ocean Nutrition Natural Formula Foods. These basically fall into two main groups:
Single-item foods; include frozen foods consisting of just one type in any pack. Among the most popular are shrimps, krill, squid, clam, beef heart, bloodworm, lobster eggs, scallops and Brine shrimp.
Formula foods; these consist of formula or recipes put together to provide a wide range of items. There are, therefore, herbivore, carnivore and omnivore formulae.
Life foods:
The reef aquarium is a complex ecosystem. The food chain is incomplete in most reef set-ups and so we must complete the chain with the food that we add to the reef aquarium. Most aquarists focus on the highest members of the food chain: the fish. This leaves the other inhabitants to get their energy through the waste products and their interaction with the air, light and minerals that are present. This makes it difficult to keep organisms such as many types of soft corals, sponges and other filter feeder species.
It is important to feed the entire inhabitants in the aquarium, from the fish to corals, filter feeder species and other microscopic organisms. This is particularly important as widespread use of modern protein skimmers take out many essential micro-nutrients. Providing a balanced diet food variety to all inhabitants will result in healthier specimens and will enable you to maintain and grow a wider selection, particularly soft corals, sponges, tube worms and other filter feeders.
Phytoplankton: Plankton is at the bottom of the food chain. At the very bottom are the phytoplankton's which comprises micro-algae and diatoms. Many filter feeders such as many Red Sea soft corals obtain most of their nutrition from phytoplankton. A number of hard to keep species such as dendronepthya will benefit from the small particle size of marine phytoplankton and is an essential part of the diet for the bivalves and sponges.
Zooplankton: The zooplankton is the next step up in the food chain and in nature they feed on phytoplankton. They are also very important for anemones and mushroom corals. Generally, the smaller the polyp, the smaller the zooplankton that can be introduced. If the phytoplankton is fed directly to the aquarium, then the natural population of zooplankton in the aquarium will multiply and the corals will benefit. There is a considerable advantage however in adding some zooplankton such as rotifer and artemia nauplii, particularly if they have been fed with phytoplankton.
Rotifer: Many professionals cultivate rotifers for filter feeding species as they are smaller in size than artemia and thus more easily assimilated. Rotifer are also essential if breeding tropical fish and are necessary for the early stages of larval growth as they are small enough to be captured by the young larvae. Once the mouth of the larvae are big enough then artemia nauplii are used. The food benefit from rotifers comes from phytoplanktons which contain the essential fatty acids that are required for larval growth.
Brine shrimp (Artemia salina) are the best known of the live foods available to marine aquarists. They are excellent, disease-free and highly nutritious. Being marine in origin themselves, Brine shrimp will survive in the aquarium, without polluting the water, until they are consumed.
If you are not sure whether your fish are getting the proper nutrition, take out the guesswork by soaking the foods in vitamin supplements to ensure your fish receive all the nutrients necessary for good and healthy growth.