Setting Up an Aquarium: Tips for Those New to the Aquarium Hobby

Are you looking for a new hobby and are you fascinated by beautifully designed underwater landscapes? Then the aquarium hobby is just right for you! You can read here how you should set up an aquarium, what you need for it, and everything you need to know.

In our overview you will find out how you can set up your aquarium step by step:

  1. Select the aquarium and determine its location;
  2. Obtain and use aquarium technology;
  3. Fill in the substrate;
  4. Hardscape: decorate the aquarium;
  5. Softscape: plant aquarium plants;
  6. Fill in lukewarm water;
  7. Dose the water conditioner and cleanse bacteria according to the instructions;
  8. Run-in phase;
  9. Insert fish;
  10. Feed the fish.

Find out in detail below about the aquarium equipment and become an aquarist!

Set up the aquarium

A few decades ago it was “fashionable” to keep goldfish in a round water glass. This type of keeping is of course absolutely unsuitable for keeping fish permanently. Round glass basins reflect sound echoes equally from all directions so that it is not possible for the fish to orientate itself using the lateral line organ. Rectangular aquariums are particularly important because the sound waves are not reflected evenly and it is easier to locate objects and possible predators.

Aquariums are available in different shapes, sizes, and decors. They are available with and without technical accessories. The classic entry-level sets are usually delivered with a lid, lighting, an internal filter, and a heating element. From a technical point of view, this is the absolute basic equipment. Depending on the size, some aquarium sets already have powerful external filters.

The top rule, however, is: the larger the aquarium, the more stable the water values ​​are and the fewer problems that arise over time. Aquariums are available from ten liters. They are called nano aquariums and are only suitable for shrimp, dwarf crabs, and snails. A beginner usually starts with a classic entry-level aquarium with an edge length of 60 x 30 x 30 cm. It then contains about 54 liters of water and represents the minimum size for caring for underwater vertebrates. However, it is not a problem to start with aquarium dimensions of 80 cm or 100 cm edge length. This of course also depends on the space available and the final size of the later fish stock. Either you have only limited space available in the room and have to adapt the stocking to your aquarium or you have chosen a certain type of fish for maintenance and adapted the aquarium to the final growth size of your fish. The last method of size selection is more satisfactory in the long run, as you can actually implement your plans and “topics” better.


Before you can set up the aquarium, a suitable location for the aquarium should be chosen. Avoid direct sunlight through windows, as well as places near the door or right next to the speakers of the hi-fi system. We recommend areas that can be comfortably observed from the dining table or couch so that you can relax and enjoy the time in front of the aquarium.

If you bought an aquarium without a base cabinet, you should use a piece of furniture as a base that can withstand the weight (every liter of water weighs one kilogram, plus decoration and gravel) and is water-repellent. Slight unevenness in the cabinet or the subsurface in the millimeter range is evened out with a fine foam mat so that there is no tension in the glass of the aquarium and cracks are avoided. Such mats are usually not required for aquarium combinations (including a base cabinet). However, a spirit level should always be used to check that the stance is straight.

Aquarium technology

Of course, an aquarium needs a lot of technology. This is the only way to guarantee a smooth “aquarium operation” and thus ensure a balanced ecosystem with healthy and colorful fish, the best water quality, and beautiful plants.

The filter

The filter is the heart of the aquarium. It circulates the water and cleaning bacteria break down highly toxic excretions. At the same time, filtering the water greatly reduces algae growth.

Internal filters are a good choice for aquariums up to 120 liters. They are mounted on the back wall of the pool using rubber suction cups and can be optically concealed by higher decorative objects and underwater plants. External filters are recommended for larger aquariums. They are in the cabinet below the aquarium and are connected to the aquarium water by hoses. The pump inside the filter container creates a water circulation to create a filter circuit. Since the container is not in the aquarium, less space is “wasted” for fish and plants, which makes the underwater world appear more harmonious. Internal filters are cleaned monthly, external filters usually once every three months.

Of course, the filter must be permanently in operation and must never be switched via a timer. Purification bacteria would die off within a short time after the filter was switched off and disrupt the equilibrium in the water.

The heating rod

The heating element is usually less responsible for heating the water than for maintaining an even and constant temperature. Day-night fluctuations are avoided by an automatic switch-off function of the heater when the minimum temperature is reached so that the small bodies are not stressed too much. Because a temperature difference of two degrees is already a big and significant difference for a fish, in contrast to humans.

The heating rod also needs a permanent power supply. This is set to the desired temperature of 24-26 ° C. It switches itself on and off automatically, depending on the temperature.

The lighting

If you want to set up an aquarium, you shouldn’t ignore the lighting. The lighting simulates sunlight. The right light sources are already included in the aquarium entry-level sets. As a rule, there are daylight tubes in warm white and cool white luminous colors. If you want to get the best possible color rendering of the colorful aquarium inhabitants, so-called color lights are ideal. Red and blue tones are particularly emphasized here so that the light in the aquarium appears much livelier and more intense. If reflectors are used in addition, the lighting intensity of the tubes increases by about twice as much. They usually have to be purchased in stores as well. For assembly, they are simply attached to the existing tubes using clips and thus they reflect the light down into the aquarium, which would be radiated from the round tube up to the cover. The result is a doubling of the brightness while the energy consumption remains the same – a very useful and efficient method to also strengthen plants in growth.

The lighting time should be a total of 10-12 hours and can be switched on and off automatically with an ordinary timer. A regular day-night rhythm is essential; the plants are dependent on sufficient brightness through the right lighting for their growth (photosynthesis). If some parameters (duration of lighting, lighting intensity, etc.) are not correct, the growth of the plants will also be disturbed. The modern LED lamp technology has already arrived in the aquarium hobby so that a contribution to low energy costs and sustainability is created here, but at the same time, all demands on brightness and color spectrum are met.

The interior

When you have obtained all the accessories, you can finally start: Now the real work starts and you can set up your aquarium. But the interior and decoration of the new aquarium should also be well thought out and planned.

The substrate

The substrate usually consists of two layers. First, a nutrient soil (fertilizer, root energy for plants) is introduced and represents about a third of the total volume of the substrate. It supplies the plants, which primarily get their energy from the roots, with all the main nutrients over a long period of time. This is followed by a layer of gravel about four to six centimeters thick (provides support for the roots of the plants). Gravel is the most common solution for entry-level or standard aquariums. The grain size of the gravel is in the best case one to two millimeters in diameter. When buying, make sure that the edges of the gravel grains should already be rounded. This is usually the case with quality aquarium gravel from well-known manufacturers. They take the trouble to heat the gravel beforehand and use a drum process to break the sharp edges and corners of the small stones. Bottom fish particularly benefit from rounded gravel, as they usually stay near the bottom and rummage through the bottom with their barbels for leftover food.

Tip: If the substrate is poured in towards the rear wall, the effect is more intense, as the floor area reaches more depth. The color can be freely selected, but natural colors such as brown, black and gray are best. Fine sand is more suitable for more special aquariums in which special types of fish such as discus fish, cichlids, rays, etc. are maintained. Since sand, due to its fine structure, quickly locks in dirt and can develop areas of rot, it should only be applied very thinly (about one to two centimeters) and freed from the leftover feed on a regular basis. With a soil calculator, you can determine which amount is the right one for your aquarium.


Other decorations as hiding places and territorial zone delimitations must never be missing and should consist of natural materials. Objects from the local forest or garden are not suitable. Old forest roots rot to 99% underwater and with stones that do not come from the specialist trade, the risk is high that inclusions of unknown substances/minerals are contained and can damage the ecosystem in an uncontrolled manner. Lava stones, natural slates, red bog roots, and mangrove roots are particularly suitable. Roots in general are also indispensable for the care of suckling catfish because catfish need the smallest wood fibers for digestion and for maintaining their organic health.

Set up an aquarium with plants

Aquarium plants are the green lungs of the aquarium and contribute to a large extent to good water quality. Sufficient stock of fast-growing plants such as waterweed, Vallisneria, and Cabomba improves the water quality and reduces the consumption of water additives and care products enormously. Rule of thumb: you should set up two to three plants per 10 liters of water in the aquarium.

Anyone who cares for many plants in different colors and shapes saves, in the long run, the use of “balancing agents”, which would have to replace the “job” of the missing plants. So-called CO2 systems, with which carbon dioxide (not to be confused with O2 / oxygen or air), help even the more demanding plants to grow splendidly and to have an intense leaf color. In the long run, these fertilizer systems are indispensable, at least for those who want to achieve really nice plant growth. A complete fertilizer and an iron fertilizer are in addition to the weekly dose. They provide the plants with everything they still need.


When you have properly filled the substrate into your aquarium, you can start with the “hardscape”. This means that you create the underwater landscape using the above-mentioned decorative items (roots, stones, etc.) and, if necessary, arrange the picture the way you like it. The “softscape” follows immediately when the plants set in. The transported material on the plant roots (cotton wool, lead rings, pots, etc.) must be removed. Use plant tweezers to stick the individual stems or tufts into the gravel. Here, too, you can test around in peace until you have found the best picture. In between, you can use a water spray bottle to prevent the plants from drying out by moistening them slightly. When the layout is in place, slowly pour lukewarm water into the aquarium. You can do this either with a hose from the tap or with a bucket. Make sure, however, that you hold one hand under the water jet so that the ground is not stirred up by the swing of the water. You can also put an old plate on the gravel floor and let the water run on it.

The structural back wall

A structural rear wall is a visually appealing element when setting up an aquarium. Depending on the size and availability, it is simply cut to fit and glued to the (rear) pane with aquarium silicone. Photo back walls are also an option, but they look far less natural but have a clear advantage in terms of price. Fish also feel much more comfortable in aquariums with a rear wall because they have better orientation/protection and thus suffer less stress.

Water additives and water care

What would an aquarium be without water? However, to ensure that the aquarium water is always in a healthy balance, regular water tests and the addition of water additives are required.

Water conditioners, filter bacteria, and plant fertilizers

Water conditioners, filter bacteria, and plant fertilizers are essential. Water from our pipes contains residues of disinfectants from waterworks and can be enriched with heavy metals on the way to the tap. A water conditioner renders these substances harmless and prevents irritation of the fish’s mucous membranes. Filter starter bacteria activate the water’s self-cleaning process. Excretions from the animals are metabolized by bacteria as food and converted into non-toxic end products. These end products are finally consumed by plants, which closes the food cycle. Further nutrients that are continuously consumed by plants must be replenished with a full plant and iron fertilizer.

Water tests

Water tests are the aquarist’s control over the functioning of the ecosystem. With easy-to-use test strips, you can quickly and easily determine the most important water values, ensuring that all circumstances really fit. Even if the water is clear, this is no guarantee of healthy environmental values. Alternatively, there are also drop tests. These are also easy to use, a little more expensive, but a lot more accurate.

The partial water change

Despite all the filter technology and maintenance work, some of the aquarium water must be changed regularly. This is because some substances cannot be used up quickly enough by bacteria or plants and, in excess, could lead to discomfort in the fish or to algae growth. With a regular partial water change with tap water of about 30% every 10-14 days, the discharge of the pollutants is guaranteed and an entry of fresh minerals from the tap water is promoted. It is also assumed that many other substances that cannot be determined with the usual aquarium water tests have an influence on the well-being of the residents. Extensive tests have repeatedly shown that regular partial water changes make it easier to maintain the aquarium and prevent subsequent problems such as the insufficient activity of the fish and fading colors.

Cleaning accessories

Cleaning accessories are used when the aquarium has to be freed from dirt, algae deposits on the panes, and leftover food. A floor vacuum practically removes dirt particles, dead plant leaves, and fodder residues; the disc magnet removes dirt on the inside of the glass, and aquarium glass cleaner helps to remove limescale and water stains.

In the next step you dose the water conditioner according to the instructions and after another hour the cleansing bacteria. These need a few days before they have multiplied in sufficient quantity in order to be able to adequately break down the dirt that occurs in the future new population. It will likely proceed in such a way that the water will be crystal clear after just a few hours. But don’t let that fool you. At this time, a kind of turf war between beneficial and harmful bacteria develops that lasts for a few days. After two to three days, this can result in milky cloudiness that can last for another two to three days. No animals may be placed in the new aquarium during this time. Rather, use this phase to familiarize yourself with the water tests. Test the water several times and write down the results. This will give you a better overview of the water chemistry. It often happens that one or the other value needs to be corrected. The water hardness is often too low or the nitrite content (NO2) is too high. Corresponding preparations for correction are available on the market for every deviation from the target value. The often-heard statement that the aids are unwanted “chemistry” can be countered by the fact that either purely biological substances are added to the aquarium or – in the case of an excess – pollutants have to be removed by means of adsorbers. Only the respective natural equilibrium of the various elements of the water is created. An endless biological cycle without care products, as many would like, is a misconception and biologically impossible. An aquarium is an artificial body of water and has to be continuously viewed “artificially”. However, that does not mean that chemistry is used.

The following water values should be aimed for a standard stocking in the freshwater aquarium:

  • pH value (acidity): 7.0
  • Carbonate hardness (KH, calcium content): 5-8 ° dKh
  • Total hardness (GH, mineral content): 6-12 ° dGh
  • Nitrite (NO2, already very toxic from small amounts): below 0.1 mg / l
  • Nitrate (NO3, from increased amounts, NO3 promotes algae growth): up to 25mg / l
  • Phosphate (PO4, from small amounts P04, promotes algae growth): up to 0.1 mg / l

Furthermore, chlorine, copper, silicate, conductivity, potassium, redox potential, oxygen, etc. can be tested. But this is only really important for advanced or very special aquariums.

Set up an aquarium with fish

The technology is in place, the water is right? Then it can finally start. The aquarium can finally be filled with pretty and colorful fish. But of course, there are a few things to consider here too.

The “running in”

An aquarium must be run in for some time before the fish are introduced. The technology in the setup pool should already be running in this phase, even without animals. There are two reasons for this: On the one hand, you can tell whether everything is working as you imagined. On the other hand, this time is important for the multiplication of the filter bacteria. If, after at least seven to ten days of running-in, all values ​​are stable for at least three days in a row, the first robust animals can be used. You can find out more about the different varieties in specialist shops. As a typical first-time stocking, armored catfish and small sucking catfish have proven to be robust. They are not so susceptible to fluctuations in the still unstable water quality. If they then feel comfortable in the aquarium for another three to four days, less robust fish can be used after testing the water parameters again. This process should be carried out in three to five stages until the final stocking is achieved after four weeks at the earliest. You can give yourself more time because your patience is required here. Otherwise, you risk tipping the water quality through feed and excrement and thus the death of your fish. The good bacteria, which are supposed to metabolize the accumulating toxins, also have a limited reproduction rate and, in contrast to other harmful bacteria, grow slowly.

The first residents

In general, you should think carefully in advance about which fish you want to keep. Note that the animals also come from different parts of the world and should not be mixed in terms of origin. When buying your animals, make sure that they come from at least the same continent, even better from a closer region, to ensure that the animals get along well with each other. Up until a few years ago, a quarantine was recommended in order to be able to observe new residents before they set in and to prevent possible infection. This procedure is no longer absolutely necessary, but can still be carried out in a separate small aquarium to be on the safe side. Otherwise, the new fish are put in a clean container (bucket) after they have been bought to get used to the new water. Every three to five minutes you fill a glass of aquarium water into the bucket until the amount of transport water has tripled. Then the new fosterlings are removed from the bucket with a net and placed in the new home. The transport water is thrown away. The lights should stay off for the rest of the day – this makes it easier for the newcomer to calm down.


Feeding the fish is also an important factor. The motto here is: little, but often. The biggest mistake that most beginners make in the hobby aquarium hobby is that they are fed too much, consequently the leftover food rot and pollutes the water environment. The rule of thumb for this is probably the most important: Anything that is not eaten within two minutes was too much and should be left out the next time. For this, you can feed one to three times a day so that the small stomachs are supplied with food for a longer period of time. But variety should not be missing: dry food, frozen food, and live food should be given alternately. To prepare the feed, it is advisable to drizzle fresh vitamin concentrates onto the feed several times a week. Fish that have suffered from stress during transport benefit from this measure in particular and diseases that can be caused by stress are optimally prevented.

Setting up an aquarium takes time

The more patience you show, the better you can set up your aquarium and experience success. All processes take a few weeks to months to be optimally coordinated; nothing can be forced in nature. Don’t let minor setbacks irritate you, they show you that nature has its clear rules and makes the hobby all the more interesting.

So you see, setting up and maintaining an aquarium is not rocket science. If you follow this guide, you will have success and fun. Just get started and enjoy your new hobby!

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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