Food must provide fish with the elements needed to "build" their body (proteins) and the energy (from proteins, carbohydrates, and lipids) required for its smooth functioning.
Feeding a fish properly ensures that it will grow satisfactorily, as well as facilitating its reproduction and helping it to combat disease. Quality and quantity are two important concepts in feeding: an aquarist must learn to avoid over-feeding and to diversify the food supply.
AQUARIUM FISH DIETS AND NUTRITIONAL REQUIREMENTS
With regard to fishes' feeding habits and dietary requirements, there are three main groups:
- Carnivores, which feed on worms, crustaceans, insects, or other fish;
- Herbivores, with a diet mainly comprising vegetable matter (plants, algae) which they graze or grind;
- Omnivores, which have a very varied diet as they eat both animal prey and vegetable matter. In practice, diets are not always so easy to define. In a natural setting fish eat what they find, and so sometimes a herbivore will eat a small animal taking shelter in the plants that it normally eats.
Carnivorous fish mainly require proteins and lipids, while herbivores have a special need for carbohydrates, and omnivores demand a mixture of proteins, carbohydrates, and lipids.
Bearing in mind the limitations of these definitions, all three diets can be found among those given to aquarium fish, although there are some exceptions. The aquarist should also take care that vitamins and mineral salts form part of a varied and balanced diet, especially through the addition of fresh or live food.
A wide palette of foodstuffs stimulates the growth and reproduction of the aquarium's inhabitants and strengthens their resistance against disease. As such, it is the best precaution that can be taken against disappointing results and lack of success.
AQUARIUM FISH FOOD PORTIONS
There is a tendency to overfeed aquarium fish and produce some rather flabby specimens. Moreover, there is an increased risk of pollution in a confined space: the more a fish eats, the more it excretes nitrogenous substances, and that is without counting the foodstuffs that quickly decompose in the water in the aquarium.
An adult fish only eats 1 or 2% of its own body weight per day, although a juvenile consumes twice that amount. Very light flakes involve little risk of overdosing, in contrast with other foodstuffs which can sometimes slip out of the hand. Whenever possible, it is advisable to divide the daily input into separate portions, twice a day for adults, more often for fry.
As fish in their natural habitat are unlikely to eat regularly every day, most aquarium fish will therefore cope well with a short term fast. Some aquarists impose a one-day fast per week to compensate for the likelihood that the fish have been overfed on the other days. Fasting is however not suitable for fry as it may slow their growth considerably.
AQUARIUM FEEDING WITH ARTIFICIAL FOOD
|Flakes of vegetable matter|
This is dry food which is commercially widely available in specialist aquarium stores. In the last twenty years the entire range has diversified considerably, and today there is a wide variety, adapted to the needs of different groups of fishes: for juvenile and adult fish, for freshwater and seawater fish, etc. These foodstuffs are characterized by a high level of proteins (generally 40-50%) and come in different forms: in flakes (the most common), granulated, or compressed.
The flakes float for a while before they sink, which makes them easier to grasp for surface and openwater fish. There are obviously also different sizes of foodstuffs, according to the size of the fish's mouth. This artificial food is fragile and deteriorates if it is not kept in the correct conditions. It must therefore be stored in a dry place protected from the light. Its composition is only guaranteed for a certain period, so it is advisable to buy a small box if
you have only one aquarium and a few fish. Some aquarists do not hesitate to
give their residents trout food, which they buy at fish farms. This food is
very rich in proteins and lipids, thus ensuring the rapid growth of trout bred
for eating, but this not vital in aquariums.
|flakes for adult heroes|
|flakes of guppies|
Although such food contains pigments intended to change the flesh color of salmon fish, aquarists who have used it have not reported any modifications in the external color of their fish. In any case, this food can prove very economical for large-scale breeding or garden ponds.
Marine fish sometimes refuse artificial food, either for a short period after their introduction to the aquarium, or on a permanent basis. One trick is to progressively incorporate increasing amounts of commercial food along with fresh food or live prey. This gradually accustoms the fish to its smell and taste until they finally accept it on its own.
DIFFERENT TYPES OF FOOD FOR AQUARIUM FISH
The artificial foodstuffs currently on the market are very effective for aquarium fish. In order to cover their needs as fully as possible, fish can also be served small, live prey, which are similarly available commercially and are an important source of vitamins and mineral salts. There are other possible options: white meat and mussels, for example.
AQUARIUM FOODSTUFFS OF NATURAL ORIGIN
Aquarium Freeze-dried food
It is possible to buy freeze-dried food items - small animals, shrimps, worms, or plankton - in which the water content has been greatly reduced so that they can be preserved more effectively. This treatment does clearly make them expensive, but they are at least as nourishing as flakes and very popular with fish. They must be stored in a dry place. Feed them to the fish according to the manufacturer's directions and do not exceed the quantities recommended.
Aquarium feeding with Frozen food
Frozen products - shrimps, fish, worms, and plankton - can also be used, once they have been separated and rinsed. They have a very high nutritional value, as freezing does not modify their composition. They are obviously stored in the freezer and must not be refrozen after thawing, in order to reduce the risk of microbial contamination. They are more expensive than freeze-dried foodstuffs.
Aquarium feeding with Domestic food items
Finally, domestic food can be provided fresh or after freezing and thawing. It is best to avoid red meats as they have too much fat. Beef heart, rich in both blood and lipids, can only be given only to large fish. White meats are preferable: chicken, turkey, or ham. As for seafood, white fish can be used - although it must be handled with care, as it can break up in the water - as well as mussels, cockles, and shrimps, which can be bought preserved naturally. Vegetables are sometimes needed for herbivorous fish: lettuce or spinach that has been blanched, i.e
Aquarium feeding with Live Prey
These are ideal food items for carnivorous fish: they retain all their nutritional value and move around to attract the fish. They are a problem to keep as they only last a few days, but they can be frozen.
LIVE PREY AND HOME PREPARATIONS
The artificial food on the market these days is very effective for aquarium fish. To diversify and balance their requirements, they can also be served some of the small, live prey that are commercially available - an important supply of vitamins and mineral salts - or fresh food or homemade mixtures.
One of the best fresh foods: mussels
This mollusk, prized by humans, is equally appreciated by fish, especially those marine species that refuse artificial food. Widely available, inexpensive, easy to freeze, mussels are a top-class dish: they are rich in proteins and carbohydrates, with few lipids.
Furthermore, they contain many minerals such as calcium, phosphorus, magnesium, iron and even vitamin C, which plays an important role in the fight against disease. Mussels must be well cooked before using and their shells and connective filaments removed. Cut them into pieces before distributing or freezing them.
Aquarium feeding with homemade food
An aquarist can easily make his or her own fish food - the possibilities are enormous. The following recipe is just one of many. Take some cooked white meat (chicken, turkey, ham) and some seafood (mussels, cockles), also cooked, and mince them with a little water to make a homogenous paste. A vitamin supplement, available from aquarium stores, can be added during this process.
This mixture can then be mixed with gelatin (from a sachet of powder, for example) so that the paste does not break up in the water, as this may become a source of pollution. One portion can be distributed immediately, while the rest can easily be frozen in ice trays. The models designed for small ice cubes are particularly recommended for making a large number of small portions. Once frozen, they can be slipped out of the ice trays and bagged up in freezer bags for use as required.
These were once very popular - so many aquarists have started with them! Nowadays they are out of fashion; in fact they are not the ideal food for fish and it is best not to use them. More complete and suitable products, particularly those in the form of flakes, are now available, even for goldfish.
Aquarium Feeding with Bloodworms
In fact, these are not worms but the aquatic larvae of various species of nonbiting mosquitoes. They are also commonly used as bait in fishing. Although it is sometimes thought that they live in mud, they are actually found in the water of areas that are well endowed with organic matter. It is useless trying to collect them yourself, but they are sold in the aquarium trade. They keep for a few days in the refrigerator, wrapped in moist newspaper. They are a good source of nutrition, as they are rich in protein.
Aquarium feeding with Tubifex worms
These are worms that are gathered from the mud in environments rich in organic matter. Some people think that they represent a risk when they are introduced into an aquarium, as they may carry undesirable bacteria. This risk is very slight, however, and there have been no reports of any serious incidents. The specimens which are commercially available can be kept for a few days in the refrigerator, in domestic water, but it is essential that this water is changed every day.
Aquarium feeding with Shrimps
Flowing and well oxygenated fresh water are home to small river shrimps of up 2 cm that swim along the banks. These are rarely sold live, but they can be found in a freeze-dried form. You will find that your fish will definitely enjoy them. The small marine shrimps found on some coasts are also highly prized, especially by marine fish. These are often sold in fishing stores along the coast. If you are lucky enough to live in such an area, you can also collect them yourself and keep them in a well oxygenated seawater aquarium.
Both types of shrimps can be frozen after being cooked and rinsed under the faucet, or they can also be ground and turned into a homemade dish.
Feeding with Small fish
Either fry or small fish can be used to feed marine fish doubtful about artificial food, or large freshwater fish. With this in mind, some aquarists breed prolific species that reproduce easily (Poeciliids, for example).
Other live prey (larger than 1 cm)
Keeping and breeding worms or insect larvae is also possible, though it sometimes proves time-consuming.
The range of live prey listed above is adequate for the needs of your fish.
Freshwater or marine plankton contain a host of organisms barely visible to the naked eye (0.1-1 cm) but valuable for feeding fish, especially the fry. Collecting them in a natural setting is tiresome, and involves a risk of introducing potential microscopic hosts into the aquarium and spreading disease. Some planktonic food is available on the market in frozen form.
This is the "magic" food that every aquarist should breed. This primitive crustacean grows to 1 cm when adult and is called Artemia salina. They live in the heavily saline waters of salt marshes, feeding on the micro-algae that they gather with their filtering legs. Their characteristic most relevant to the aquarist is that their eggs can be stored dry, with their development interrupted, for use later on. Once the eggs are returned to salty water, they hatch rapidly and produce a larva called a nauplius, which measures only 0.3 mm and is particularly suitable for feeding to fry.
Feeding brine shrimps to fish is easy, even for an amateur (see box). They are still too big for the fry of some fish, however, especially marine species. In such cases, it is possible to use rotifers, animals halfway between worms and crustaceans, which have a crustacean-like shell and never grow to more than 0.2 mm.
These are more complicated to breed than brine shrimps, as they must be fed planktonic micro-algae which also need to be cultivated. It is therefore best to obtain them from a laboratory specializing in oceanography or marine biology, and to get advice on the essential steps required to look after them for a few days – the time within which the fry for which they are intended will be big enough and sufficiently sufficiently developed to move on to a diet of brine shrimp nauplii.
Aquarium Food Distribution
When they are healthy and well-adjusted to captivity, fish eat at a regular time and become accustomed to the spot where the food is given out. It is advisable to divide the daily ration into two parts - one in the morning and one in the evening, for example. The end of the day - 1 or 2 hours before turning the aquarium lighting off - is usually the most practical for the aquarist. In any event, food distribution offers a special opportunity to observe the behavior of your residents and check their state of health.
Allowing the fish to come and feed out of your hand is particularly enjoyable, but take care, because some large specimens have impressive teeth! If the water is too agitated, artificial or natural food may be dispersed too quickly and washed to a corner of the aquarium where the fish will not be able to recover it. Thereby creating a potential for pollution. The stirring of the water must therefore cease when food is being distributed and eaten.
Feeding the fry
When they are born, the fry of egg-laying fish feed on the reserves in their vitellin vesicle, as their mouth does not open until a few days later. They will then often accept the fine powders which are available commercially. If this is not the case. Give them brine shrimp nauplii for a few days – newly hatched nauplii are most suitable for the first two days. After that, they can be offered nauplii that are 48 hours old.
Daily production over a period of several days must therefore be planned for. If brine shrimps are unavailable, another option is the production of infusorians. Live-bearing fish (the Poeciliid family) accept artificial food from birth, and they also thrive on brine shrimp nauplii. As for marine fish, rotifers, discussed above, should be used, as they easily fit into the small mouths of the fry.
BREEDING BRINE SHRIMPS
The dry eggs (known as cysts) are available in aquarium supply stores. They must be kept away from light and moisture. In order to make them hatch, salt water must be prepared with the following characteristics: temperature 25°C, salinity
35%, i.e. a specific gravity of 1.023. The salt water can be natural or reconstituted with special aquarium salts, or even with rough kitchen salt (easier for aquarists who do not keep marine fish).
The water can be colder and less salty (up to 20°C and 20%, i.e. a specific gravity of 1.014), but the hatching rate will be lower (50-60% against 80-90%). Any small glass or PVC container can be used - bottles, for example - although specialist equipment is available. The eggs are placed in the still water for a quarter of an hour, the time required for their rehydration. If we estimate that 250,000 eggs weigh around 1 g, a tiny amount (the tip of a knife, for example) will produce sufficient brine shrimps.
Aerate the water slightly to produce small bubbles, which will disperse the eggs, but be careful not to stir the water too vigorously, otherwise some of the eggs will crash against the sides of the container and will not hatch. The hatching occurs after 24 36 hours at 25°C, or after up to 48 hours at 20°C.
Finally, switch off the aeration: the empty shells will float to the surface, the unhatched eggs will fall to the bottom, and the brine shrimp nauplii will be swimming just under the surface. It is then easy to siphon them off (with an aeration pipe, for example) and strain them through a small filter (available commercially), or, alternatively, through the thin mesh of a piece of old curtain, or even a very fine pantyhose. To make this operation easier, you can group the nauplii together using a flashlight, as they are attracted by light. You can then go on to feed them to the fry. They will only survive for a few minutes outside salted water, and they will not eat on the first day after hatching.
If you want to keep them for several days to obtain larger or more mature larvae, special food is commercially available. This makes it possible to keep brine shrimps until they are adults this operation easier, you can group the nauplii together using a flashlight, as they are attracted by light. You can then go on to feed them to the fry. They will only survive for a few minutes outside
ADULT BRINE SHRIMPS
Adult brine shrimps are sold live in small sealed sachets containing salt water and air. They are passed through a sieve before being given to the fish, which enjoy hunting them down. They survive for a few minutes in unsalted water. Brine shrimps can also be bought frozen.
When feeding, it is important to avoid any overdosing, whether with artificial food or live prey, such as the adult brine shrimps pictured here.
These are microscopic, unicellular animals, easy to produce in fresh water. They are usually present in small numbers in an aquarium. Riccia, a surface plant, gives them a chance to grow, as they find food (organicmatter) on its leaves. They can also be produced by leaving a piece of potato, a lettuce leaf, or some paddy rice (unhusked rice, available in grain stores) to soak in a receptacle containing aquarium water.
What if a fish does not eat?
Sometimes a fish refuses to eat, or appears to be incapable of doing so. It is therefore a question of finding the cause and eliminating it. A newcomer to a tank rarely eats on the first day. This is normal, as it feels lost in its new environment. Small species and more lethargic fish are often dominated by their bigger and faster cohabitants at feeding time.
They must therefore always be fed separately, preferably with mobile, live prey, once the other fish have been distracted by other food. A fish can also refuse to eat if it is sick, and this will be reflected in its behavior, color, and other symptoms which may eventually be seen on its body. In this situation it must be isolated in another aquarium, treated, and given rich food. Comprised of live prey or fresh produce. Sometimes fish can systematically refuse to eat artificial food, although this is rare in fresh water, but less so in marine aquariums. There is no point in being stubborn: change to a varied diet based on live prey and homemade fare.
GOLDEN RULES FOR FEEDING AQUARIUM FISH
- Give fish a varied diet;
- Give them a little, but often. Two portions a day is ideal. For fry, the feeding can be more frequent.
- Do not wait until the fish are sated and stop eating. Stop feeding once the ration is complete;
- Siphon off any food surplus as quickly as possible, as the leftovers are pollutants.
A MIRACLE FOOD FOR FRY
A hard-boiled egg yolk is added to water in a glass. This forms microparticles which are then sieved.
This nutritious liquid is then given to the fry, taking care not to put too much into the tank, as it is always important to minimize pollution. Egg yolk, rich in proteinsm and lipids, can be used as a complement or as a replacement for other food.