▷ Aquarium Fish Questions for Beginners | All information and details

How many fish can you keep in an aquarium?

© Lukas Knechtle

The exact number of fish that can be kept in an aquarium depends on the species of fish desired.

As a rule of thumb for beginners, it is recommended to calculate at least 2 liters of water for one centimeter of fish.

The amount of water available in the aquarium is calculated as the content of the aquarium minus the thickness of the pane and minus the decoration.

The size of the later adult fish is calculated as the fish size. In addition, the demands and behavior of the fish must be taken into account.

Some fish species, e.g. B. Armored catfish and many tetras only feel comfortable in groups and at least 5 to 7 animals of these species should be kept together.

Examples of a typical beginner’s aquarium

As a rule of thumb, a typical beginner’s aquarium with a water volume of around 50 liters can hold a maximum of around 5 fish of around 5 cm in size. If dwarf cichlids are to be kept, a maximum of one male and one female can be kept.

Appropriately sized tetras can be kept in a small school of 5 to 7 fish. This can e.g. B. neons or cherry spot tetras. Livebearers like Heterandria formosa can be kept in a larger group. Keeping killifish in a group of one male and three females is also interesting.

Further stocking suggestions can be found in the sample aquariums section.

How are baby fish fed?

Guppy cub Photo: Jürgen Colling

Liquizell is a suitable food for young fish that are smaller than 2 mm.

Slightly larger young fish can already eat so-called dust (dry) food, which is offered by various food manufacturers.

Finely ground flake food serves the same purpose.

In addition, young fish eat microorganisms in the aquarium that are invisible without a microscope and e.g. B. live on plants, roots and stones.

Do young fish have to be placed in a spawning net or spawning box?

As a rule, novices are guppies or platys who first have cubs. The young of guppies are initially pale and colorless, platybabies are red from the start like their parents. Since both species have numerous new young animals at regular intervals, it is sufficient to offer a few hiding places in the aquarium. In addition to dense plant growth or the roots of floating plants, some loose filter floss can also be hung in the aquarium.

The cotton is tied to the cover or a floating, non-toxic object (ping pong ball, etc.) with a string. Since the juvenile fish gather in the middle layers of the water and under the surface, they can quickly get to safety thanks to their good flight instinct.

Show hiding places* Roots and cave for the aquarium

When can young fish be placed with the other fish?

As soon as the young fish can no longer be eaten by the other fish, ie no longer fit in their mouths, young and old fish can be kept together. For guppies and platies, this is about the size of the head of the largest adult guppie or platie.

What types of fish are good to start with?

Young catfish Photo: Angela Adomeit

Above all, fish for aquaristic beginners must be robust and also tolerate minor maintenance mistakes. In addition, even beginners have different tastes. Guppies and platies are popular and suitable as beginner fish. They are lively, have strong colors and tolerate most water qualities coming from the water pipes in Central Europe. A small group of guppies or platies can be kept in an aquarium of 60 x 30 x 30 cm. It is enough to start with a couple of guppies and a couple of platys, because they breed easily even in a beginner’s aquarium. Since they give birth to live young, they are referred to as livebearers. In small aquariums, due to the rapid reproduction, there is even a risk that there will soon be too many fish in the aquarium and the typical dangers of an overstocked aquarium will occur. Especially if there are some hiding places for the young fish so that they are not eaten by the parents or other fish.

© Mirko Rosenau Fotolia.com

The risk of overstocking is avoided if the first fish z. B. zebrafish and harlequin barbs can be selected. These species do not impose any demanding conditions on the water quality either. The colors of these species may not be as striking to beginners as guppies and platies. On closer inspection, however, they turn out to be beautiful and interesting fish. Especially the zebrafish are always lively in the aquarium. For this reason, a 60 cm long aquarium represents the absolute lower limit in which 5 to 7 animals of one of these species are placed at the beginning.

An aquarium with a length of 80 cm is better, in which more animals can be placed accordingly. Since these two species shed eggs, reproduction is more difficult than in the livebearers. In a normal beginner’s tank, a young fish will only rarely grow large, since the eggs and young are eaten very quickly. However, initial breeding experience can be gained with zebrafish if e.g. For example, a pair can be placed in a small breeding aquarium to spawn.

After spawning, the parents are removed from the breeding aquarium.

© Mirko Rosenau – Fotolia

The same applies to some of the more robust species of tetras, such as B. Starspot Tetra and Rio Red.

An alternative to the usual recommendations for beginners is the killifish, which belongs to the killifish family. While the males are splendidly colored, the females are quite inconspicuous.

A male with 2 – 3 females can be placed in a well-vegetated aquarium of 60 cm length with hiding places. If java moss is present in the aquarium, there is a good chance that the mollies will multiply and that a young animal will be able to hide from its fellow fish from time to time until it is too big to be eaten.

The reproduction rate is therefore significantly lower than that of livebearers, but you can still enjoy young animals every now and then.

Please do not make fish soup

An aquarium should not contain too many fish or too many different types of fish together. Many species only feel comfortable in groups of about seven animals or more. Larger groups of one or a few fish species also look better than just one or two animals of many different species.

Consider the demands of the fish

The areas of origin of the aquarium fish have bodies of water with sometimes extremely different properties. The water from the African Lake Malawi is completely different from the water from the South American Amazon. The tap water in Central Europe also shows large differences in some cases. While the water in Kaiserslautern z. B. is relatively soft, there is very hard water in Würzburg.

When selecting the fish, the demands of the fish must be compared with the existing water parameters. Fish kept in unsuitable water are susceptible to disease. tetras such as B. Red tetras generally prefer soft water, while livebearers like guppies tend to prefer harder water.

Do damaged fins grow back?

It sometimes happens that the fins of the fish are damaged. These can be small holes in the fins, but it can also go so far that the fins are completely frayed. This can be caused by bite wounds in ranking fights or diseases such as fin rot.

If only the soft parts of the fins are damaged, the damage usually heals fairly quickly if the keeping conditions are good and the fins grow back. If the hard fin rays are damaged or even the base of the fin is damaged, the fins may grow crippled or not grow at all.

Comparable are human fingernails. If only the nail is damaged, it will heal. Damage to the nail bed usually does not heal completely.

Why do fish swim at an angle in the dark?

At dusk or in the dark, the fish in the aquarium often swim slightly tilted to the side or with their heads down.

Since in nature the light always comes from above, the body alignment is simply based on the light.

This is how fish swim upright in nature. Light enters an aquarium from the side at dusk or in the dark.

Since the fish orientate themselves as usual using the incident light, they align themselves in the direction of the light source and swim to the side or lean forward depending on the incidence of light.

Beginner fish in the aquarium (instructions for young aquarists)

You can make good use of the time until fish can be placed in your aquarium. Go often to different pet shops and take your time to look at the fish. After a while you will recognize in which shop the fish are lively, where the fish hold their fins very close to their bodies because they do not feel well, or where dead fish can often be seen. You can then also hear whether the seller is advising people and explains everything well, or whether he only wants to sell as many fish as he can. Only buy your fish where the fish look healthy and the sellers know fish themselves.

There are so many fish that it is impossible for me to describe them all. There are no good or bad fish either. All fish have their advantages and disadvantages. So that you can choose the right fish for you, I will now write something about particularly popular fish.

Guppies, Platies and Black Mollies

These fish are beautifully colored and many people find them beautiful. They often give birth to young in the aquarium. The young are easy to raise.