How to choose ornamental fish food? Essential breeding knowledge explained in one go

Whether goldfish or tropical fish, in terms of their feeding habits they can all be divided into three major categories, namely carnivorous, herbivorous and omnivorous. But carnivorous and omnivorous types predominate, and only very few fish feed exclusively on purely plant-based food. Once you understand the feeding habits of the fish you keep, you need to consider what specific food to use. The foods commonly used to feed fish can also broadly be divided into three categories: natural animal-based food, plant-based food and artificial food.

1. Animal-based food

There are many kinds of animal-based food, ranging from protozoa invisible to the naked eye to large fish, all of which can be used as food to feed fish.

(1) Protozoa

Common aquatic protozoa include paramecium, amoeba, arcella, vorticella, rotifers, water rotifers and so on. These zooplankton often float densely on the surface of sewage water at dawn in late spring and early summer, forming egg-yellow flakes known as "gray water", also called egg-yolk water. They can be caught around daybreak and are the most ideal food for feeding newly hatched fry. There are many kinds of rotifers, and individuals are also larger than those in "gray water", but they are not suited to being kept long and die easily after being caught.

(2) Water fleas

Water fleas belong to the copepods and cladocerans among arthropods; their individuals are somewhat larger and their vitality is also stronger. Several common kinds of fleas can be seen in Figures 21 and 22. These can live in the aquarium and feed on phytoplankton in the water, which also helps purify the water quality. Cyclops belongs to the copepods; this type of animal also has many species, and its body is bluish. When swimming it jumps and then pauses, so it is also called "blue jumper". In short, this type of water flea is a kind of food rich in nutrition, containing various amino acids, fats and calcium. Using them to raise fish gives very good results, but "blue jumpers" die easily and rot, separating out oils on the water surface; after these oil droplets spread they form a surface film that cuts off contact between water and air, thereby affecting the dissolved oxygen content in the water. Therefore do not feed too much.

(3) Earthworms

Earthworms include terrestrial and aquatic species. Terrestrial earthworms can also be used to feed fish, although some fish accustomed to eating live foods may not be used to earthworms at first, they soon adapt. When using earthworms to feed smaller fish, they should first be chopped up. Aquatic earthworms are a common fish bait on the fish market; their bodies are red and as long and thin as threads, so they are also called red thread worms or red line worms. Because aquatic earthworms live in sludge, their bodies are rather dirty, so they must be rinsed repeatedly before feeding. Moreover, when feeding they should be placed in a feeding box suspended in the aquarium; when the thread worms crawl out through the small holes in the bottom of the feeding box, they can immediately be eaten by the fish. In this way the red thread worms can be prevented from burrowing into the sand at the bottom of the aquarium, keeping the water clean.

(4) Insect larvae:

The larvae of many insects are also good food for fish. For example, fly larvae are tender and nutritious, and are good food for fattening fish. Mosquito larvae are something people did not pay much attention to in the past, but in fact their bodies contain abundant protein (over 80%). If they are mixed into the food and put into the aquarium together, the first thing the fish eat is them. Bloodworms are the larvae of chironomid midges; their bodies are about 1-2 cm long, cylindrical, and red all over. In the north they are also called "oil fleas". The nutritional value of bloodworms is quite high; in addition to being rich in protein, fat and vitamins, their bodies also contain an aromatic substance, which gives them good palatability for fish. They are most suitable for medium-sized or large fish to eat.

(5) Other animal-based foods:

Besides the various fresh live foods mentioned above, egg yolk, meat chunks and animal liver are also foods fish like to eat. When live food is scarce, meat chunks or animal liver can be chopped up and fed. Egg yolk should be boiled, mashed, dried, stored in a sealed glass bottle, and fed as needed. In addition, dried fish worms, dried crab roe and so on can also be used. These dried feeds are nutritious and convenient to store. But before feeding, check carefully to see whether they have spoiled, and never feed dried feed that has already spoiled and has a rancid smell.

2. Plant-based food

There are also many kinds of plant-based food suitable for omnivorous or herbivorous fish. Many of the algae growing in the aquarium are food for fish. But their quantity is limited, and especially for omnivorous fish it is far from enough. Therefore some other plant-based foods with wide sources, low cost and suitability for preparation and storage should be chosen as supplementary food for fish. For example, spinach contains a large amount of vitamins and is very easy to obtain; it can be blanched briefly, chopped and fed, so spinach is a very good plant-based food, and fish that eat spinach can also have their constitution strengthened. Soy milk is also a nutrient-rich food; it is a liquid made by soaking soybeans and grinding them. Soy milk is suitable for feeding fry and can also be used in large-scale fish ponds or pools. But when feeding soy milk, the feeding amount must be strictly controlled to avoid polluting the water quality. In addition, foods without oil such as noodles, rice and steamed bun crumbs can be ground up and used as fish food. But because fish do not especially like to eat them, the feeding amount should not be too much; if too much is fed, it will instead cause the water to deteriorate. Of course, foods like popcorn are very fun, can float on the water surface, and will not pollute the water quality, so they are also fairly ideal food.

3. Artificial food

Artificial food can actually be divided into two kinds: artificially cultured live animal food and artificial compound food. When feeding fish, it is best to mainly use fresh live food; especially for beginners, this point is even more important. However, at present the quantity of artificially cultured live food is still very limited, and sometimes artificial compound food is needed to feed fish. If you have doubts about whether the artificial compound food sold on the market contains all the nutrients needed for fish growth, you can also make compound food yourself.

There are many raw materials for making artificial food, such as pig liver, shrimp meat, fish meat, crab roe, egg yolk, chicken blood, bovine blood and so on. When making it, cook these substances in boiling water, dry them in the sun, make them into granular form, then sift these granules and put granules of different sizes into bottles separately; then they can be used to feed fish. If made into granules again, the feeding effect will be even better.

Several commonly used artificial food formulas are introduced below.

Formula 1: fish meal 37.5 g, shrimp meal 37.5 g, liver (preferably beef liver) 37.5 g, spinach 19 g, 1 egg, flour 112.5 g. Mix the above substances, add water, make into granules, and dry in the sun to obtain the finished product. To increase nutrition, brewer's yeast and vitamin B can also be added.

Formula 2: defatted silkworm pupa meal 30%, barley meal 60%, fish meal 10%, some vitamins, some salt.

Formula 3: pig and bovine blood meal 30%, fish meal 30%, egg 10%, tofu powder 10%, flour 19.5%, mineral salt 0.3%, multivitamins 0.1%, calcium 0.1%

Of course, when making fish food yourself, each place should also determine the composition of the formula according to the specific local raw materials, but the nutritional value should be as complete as possible. Whether self-made artificial food or commercially sold artificial food, although they can make up for the shortage of natural food, they easily cause water quality to deteriorate, so the feeding amount should be controlled, especially for units specializing in fish production; of course it is more suitable for large fish farms.

In addition, what kind of food to feed different fish also depends on the species and size of the fish. Newly born ovoviviparous fish can be fed on the second day, while for egg-laying fish, feeding should wait until 4 or 5 days after the fry have basically absorbed the yolk sac (closed belly). For fry and small fish, it is best to feed gray water at first. As the fish grow, the food can be changed to medium-sized live food or dried small shrimp, small fish, and so on. For large carnivorous fish, larger shrimp, loach, meat chunks and other foods can be fed. Besides the foods mentioned above, marine fish can also feed on seaweed, coral, sponges and so on. When feeding, pay attention to adjusting the food; when fish do not eat a certain food, other food should be substituted.