Acclimatization of Fish in the Aquarium

You can do a lot wrong when buying and placing ornamental fish. However, if you take a few precautionary measures, you will be much more likely to enjoy seeing your new animals swimming around safe and sound in your aquarium. This is how the acclimatization of fish in the aquarium succeeds.

Open your eyes when buying fish!

You are really well-advised if you keep your eyes open when buying the ornamental fish you want. You can avoid a lot of problems from the outset if you look very carefully at the animals in the sales aquarium beforehand. Do all fish show normal behavior and do their fins spread naturally? Are you in good nutrition or are you very emaciated? Are there any fish showing signs of illness? If so, then you should stay away from it from the start. Only buy fish that are obviously healthy and take some time to observe them.

Quarantine is always better

In principle, nobody can say with certainty whether a freshly purchased fish is completely healthy. Most of the ornamental fish in the pet trade are imports, even if they are bred. Even if you don’t look at a fish, there may be pathogens and parasites present at any time, with which a healthy animal usually gets along well. Under stress – and being caught and transported in a transport bag as well as getting used to a new environment are such stress factors – weakness parasites can quickly multiply en masse on newly acquired fish.
In this respect, a quarantine in a separate quarantine aquarium is always the best and safest solution to accommodate newly acquired fish and prevent diseases from being introduced into the community aquarium. You should keep the fish in it for yourself for at least a week and watch carefully whether they are behaving normally and accepting food. I am aware, however, that not all aquarists can set up their own quarantine aquarium. Should you not be able to do that, then the previously mentioned very precise observation when buying is all the more important.

Protect the transport bag after purchase!

When you buy new ornamental fish in a pet shop, they are usually packed in a transport bag. You should be very careful that the fish survive the transport to your home. The bag should therefore be protected from light and heat loss by outer packaging (e.g. made of newspaper). This is especially important in the cold season. Then it is particularly important that the animals are brought to you as quickly as possible so that the water does not cool down. Water temperatures below 18 ° C are usually critical. This can lead to losses in heat-loving fish. You should also make sure that the bag and the fish in it are not shaken too vigorously, as this causes further stress.

What happens during a long transport in a transport bag?

With a relatively short transport from your trusted zoo dealer to your aquarium, the aquarium water may cool down a bit, but no major changes happen in the transport bag.

The situation is different, however, if the animals remain in a transport bag for many hours, for example during a longer transport or if the animals are ordered online. Then chemical processes take place in the water, which must be observed as a result. This is because the animals give off metabolic products to the water, which, depending on the pH value of the water, are present in the water as ammonium or ammonia. In the aquarium, nitrifying bacteria would quickly convert them to nitrite and then further to nitrate, which is less toxic to fish and ultimately has to be removed by changing the water regularly.

This conversion cannot take place in the fish transport bag and therefore we only find ammonium or ammonia. The ratio depends on the pH of the water. At a high pH value, ammonia, which is very toxic to fish, is in the majority, while a lower pH value allows the less harmful ammonia to appear more intensely. Fortunately, the breathing of the fish in the bag also constantly increases the carbon dioxide value, and the resulting carbonic acid fortunately also lowers the pH value.

However, if we open the bag after a long transport of fish and many suspected metabolic products, it should be quick to remove the fish from the transport water. Because the carbon dioxide escapes, the pH value rises, ammonium converts into ammonia and may poison the fish.

How do I best use the animals?

First of all, you should make sure that the water temperature in the bag is adjusted to that in the aquarium because too high-temperature differences when moving can be very damaging to the fish. Therefore, simply lay the bag unopened on the surface of the water until the water in the bag feels about the same warm.

Many aquarists then empty the contents of the bag with fish in a bucket and let water from the aquarium drip into this container through an air hose with reduced diameter, so that the water values ​​adjust very slowly and gently. Theoretically, this droplet method would be a good and very gentle idea, but it takes so long that the fish can initially have been poisoned by the high ammonia content until they are sufficiently mixed.

Use robust fish

As hard as it sounds, for robust fish, immediately pouring it off with a fishing net and immediately transferring it to the aquarium is the much gentler method. You should pour the contaminated water down the sink.

Use sensitive ornamental fish

But how do you deal with more sensitive ornamental fish, which can be damaged in the process, as they may not tolerate a sharp change in hardness and pH value? For these fish (for example some dwarf cichlids) you can purchase one of several products available from pet shops to eliminate ammonia. If you have added this agent after opening the bag and prevented poisoning, the droplet method for equalizing the water values ​​is by far the best method. Excess water in the bucket is poured off again and again until the fish swim almost in pure aquarium water and can be caught and transferred.

It is best to darken the aquarium when inserting the animals

When new fish are introduced, the animals already living in the aquarium sometimes chase after them and can injure them. However, you can easily prevent this by immediately darkening the aquarium and letting the animals rest.

Conclusion on the acclimatization of fish in the aquarium

As you can see, a lot of mistakes can be made when acquiring and putting in fish, but they are easy to prevent. However, if you take a few precautions, you are unlikely to have any major problems with your newcomers.

Mary Allen

Written by Mary Allen

Hello, I'm Mary! I've cared for many pet species including dogs, cats, guinea pigs, fish, and bearded dragons. I also have ten pets of my own currently. I've written many topics in this space including how-tos, informational articles, care guides, breed guides, and more.

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