Diets and food needs
By their diet, there are 3 kinds of fish:
- carnivorous fish, which eat insects, worms, shell-fish and other small fish
- herbivorous fish, which eat vegetables (plants or algae)
- omnivorous fish, which have a much diversified diet because they eat both vegetal and animal food.
It`s hard to define the diet. In nature, fish eat what they can find. That way the herbivorous fish eat sometimes small insects which can be found between the plants. The carnivorous fish especially need proteins and lipids, the herbivorous ones need especially glucose and the omnivorous fish need all 3 kinds: proteins, lipids and glucose.
These 3 diets can be found at aquarium fish too, with some exceptions. You shouldn`t forget about the vitamins and minerals which should be provided by a healthy diet. A diversified food provides the necessary elements for a good growth and breed, and also it helps preventing the diseases. In conclusion, diversified food helps the equilibrium from the aquarium.
There is a temptation of over feed the fish, resulting fat ones. This way, the risk of polluting the environment increases (a fish eating a lot will produce a proportional quantity of excrements).
An adult fish can only eat 1-2% quantity of its body weight in one day, and double if it is young. The plants are very light, they don`t present the risk of over feed, and the problem is only with the other foods. It`s recommended to program the food over the day; 2 times for adults and more times for young ones.
Fish can easily handle short periods of hunger, because of the probability that in their natural environment could be the same conditions of less food. Some aquarium fish breeder set a day in the week when they don`t feed their fish, just in case of over feed in the other days. Young offspring can suffer if they are not fed, causing them low development.
It`s about dry food sold out in aquaria markets/shops. They have diversified a lot in the last twenty years. Nowadays there are lots of food sets for each class of fish: fry and adults, freshwater fish and saltwater fish, etc… These foods are rich in proteins (40 to 50%) and have different forms: dehydrated foods (the most common), tablets or met feather shot. The dry food floats for a while, and then it submerges facilitating the feeding of surface and middle depth fish. Met feather shot submerge faster facilitating the feeding of middle depth and bottom fish. There are more sizes for the foods, depending on the size of the mouth. Artificial food is fragile; it degrades if it is kept in inadequate spaces. They must be kept in dry and darken spaces and it`s better to buy a medium size box if we have few fish…
Some of the tropical fish breeders feed their fish with trout food which they get from piscicultural farms. These foods, rich in lipids, favor a fast grow of the trouts which are breed for human feeding , but which is not the essential scope of aquaria. Even if these foods contain pigments which are used to color the skin of trout, the aquarium fish breeders who used them say they didn`t notice any coloration of their fish skin. Anyway, this kind of feeding is economic at industrial scale or for garden ponds.
Sometimes, the marine fish permanently or a certain period, refuse the artificial food after they are introduced in aquariums. A solution for this problem is administrating both artificial and natural food and, in time, reduce the quantity of natural food.
Fish can be fed with frozen shrimps, fish, worms, plankton after they are selected and cleaned. Their nutritional value is very high because the freezing doesn`t change their composition. They are kept in the refrigerator and they don`t need refreeze after defreeze. This kind of food is quite expensive in comparison with other kinds of food.
Home made food
In this last category, we have foods which can be administrated fresh or after freezing and defreeze. You have to avoid red meat and too greasy meats. Beast heart, rich in blood and lipids, will only be used for big fish. White meats are preferred: chicken, turkey, ham. From marine, we can use white fish, mollusks, shells, shrimps, which we can buy as tinned. Vegetal foods are needed for herbivorous fish because these aliments are rich in vitamins and minerals. We`ll use salad or spinach which has to be boiled for a few minutes.
Vitamins are very important for fish feeding as for human feeding. They have a use in skeleton developing; they help the growing and strengthen the resistance to diseases. A tropical fish which suffers of a vitamin lack will weaken, and this thing isn`t visible at the beginning. The vitamins degrade under the action of heat, oxygen and light. That`s why the main intake will be made by fresh foods, living food or frozen foods.
Actually, they are not worms but aquatic larva of different mosquito species. They are known as fishing bait. Contrary to their name, they don`t live in dung but in the water from areas which are rich in organic materials. You don`t have to look for them because you can find them in aquaria markets/stores. They are kept for a few days in newspaper wet paper in the fridge. They are good foods, rich in proteins, much appreciated and looked for by all aquarium fish.
These worms are taken from ooze which is rich in organic materials. Some tropical fish breeders consider that these worms represent a risk for the aquarium, because they can bring in unwanted bacteria. This risk remains limited because there haven`t been reported any severe accidents. The worms which can be found in shops are kept in fresh water for a few days at low temperatures in the fridge, but it`s very important to change the water daily in order to avoid their degradation. They are much appreciated by most of the aquarium fish.
In well oxygenated freshwaters there are some small shrimps with a size of 1-2 cm which swim laterally. These are the freshwater shrimps. Rarely are they sold alive, but they can be found in aquaria shops. Even you can catch them and give to the fish which appreciate them very much. There are some saltwater shrimps in the Romanian part of the Black Sea, which are appreciated especially by saltwater fish. Sometimes, they are sold at the fishing stores from the sea side. The ones who live in those are can catch them and keep them in aquariums with oxygenated saltwater. These two kinds of shrimps can be boiled and rinsed out with fresh water and after that you can mix them in order to obtain a home made food.
For feeding marine fish, which refuse artificial foods, or big freshwater fish, we can use small fish. For doing this, some fish breeders with better experience breed prolific species, which reproduction is done easily in aquariums (Poeciliidae for examp…)
Freshwater planktons or saltwater planktons contain multiple organisms which can hardly be seen (0.1-1 cm), but interesting for feeding our aquarium fish, especially the fry. In natural environment there is a big quantity, but there is a risk of bringing microorganisms that induce diseases in the aquarium. Some planktons can be found for sale in aquaria shops/markets.
Breeding baby brine shrimp (Artemia salina)
Dry eggs (called cysts) can be found in aquaria shops/markets. They must be kept in dry and dark places. In order to hatch, we`ll have to prepare saltwater with a temperature of 25° C, 3.5% salt, a density of 1023 g/l. The water can be natural, with special salt for aquaria, or you can use normal salt (easier if you don`t have marine aquariums). The water can be colder and less salty (20° C and 2% salt, density 1014), but the percentage of hatching is lower (50-60% in comparison with 80-90% if the first conditions are realized). We can use any plastic or glass tank with a small volume, though there are specialized tanks in aquaria shops. The eggs must be kept in calm water for a few minutes in order to re hydrate them. Knowing that 250.000 eggs weigh about 1 g, a small quantity is enough for breeding artemias for a generation of fry. The water is agitated with an air pomp which generates bubbles.
A big pressure will throw the eggs on the laterals making their hatching impossible. The hatching takes place in 24-36 hours at a temperature of 25° C, and 48 hours at a temperature of 20° C. At this moment you`ll have to stop the air pomp. The shells will float, the unhatched eggs will submerge and the artemias will swim at medium depth. In order to give the artemias to fish we can put all the artemias together using a pocket lantern. Artemias can live in freshwater just a few minutes. In the first day artemia doesn`t eat. You can feed your artemias with specialized food from aquaria shops and you can have adult artemias.
They are unicellular microscopic organisms. They represent a small quantity in the aquarium. Riccia, a floating plant, permits their developing because they can find food on the plant`s leaves. You can also get paramecium if you put some old aquarium water in a tank and introduce there salad leaf or paddy rice (unpeeled rice available in specialized shops from larger cities). The paramecium represents the perfect food for the fry.
A marvel food for fry
It`s about the yolk of egg, boiled, firm and put in a glass of water. Some micro particles form, which are get through a sifter which keeps the big particles. This soup is given to fry making sure we don`t pollute the aquarium. The yolk of egg, rich in proteins and lipids, can supply other foods. This food is very nourishing and it is indicated to all tropical fish breeders.
What can we do if a fish doesn`t eat?!
Sometimes it may happen that a fish refuses the food or can`t eat it. We have to search and cross out the cause. A new fish, recently introduced in the aquarium rarely feeds from the first day: it`s a normal fact because it feels lost in the new environment. The small species and the less active fish are dominated by big and active fish while wee feed them. In this case we have to feed them separately, better with small living food, after we distract the other fish attention with other foods.
A fish can refuse the food because it has a disease, which can be easily remarked. In this case we have to put the fish in a separate tank and feed it with lot of fresh living food.