Setting up a Fishtank – How to start a aquarium

Set up and start your fishtank: our guide to the first fish!

Finally: You fought with yourself for a long time (and maybe also against your wife) and now you decided to buy a fishtank - but what now? Even before buying a tank, there are many things to consider, from the selection of the right fishtank size to the right location, many decisions have to be made. But also after the purchase of a tank many stumbling traps are to be avoided. Above all by overzealous salesmen the run-in phase is overlooked and with the first dead fish the desire at fishkeeping lost itself fast. Admittedly, that would be the worst case scenario. Nevertheless, it is recommended to read the following guide completely in order to avoid possible beginners' errors.

Table of Contents

Choose the right size of the fishtank

It depends on the space available in the apartment and of course also on the available budget: a complete fishtank set with a length of 24 Inches costs around $50-150 at the moment, while a complete fishtank set with a length of 48 Inches starts at around $350. Also the size of the tank is important: a room with an area of less than 20 m² should be equipped with a tank with a length of less than 48 Inches and a room with an area of less than 10 m² should be equipped with a tank with a length of less than 36 Inches.

If you want to care for a certain kind of fish or a certain group of animals, the size depends on the needs of these freshwater fish. A larger pool is relatively easier to maintain than a smaller one, because the necessary maintenance work is usually less frequent. If it can be realized somehow, you should start with a basin of at least 36 Inches in length (approx. 40 gallons of water).

Scalare in the Fishtank

The choice of location

The adaptation of the tank types to the interior has become easy thanks to the modern glass aquariums, whose panes are glued with silicone rubber. The industry's versatile aquarium furniture range also adapts well to the various types of wood and styles. Before setting up the aquarium, however, the following aspects should be taken into account:

  • Do not choose a location that is too sunny, as the sun causes a great heat up and contributes significantly to algae growth. Modern aquarium lighting is independent of daylight.
  • Do not place the pool directly on, above radiators or on an oven.
  • A sink, washbasin or toilet should be within easy reach (up to approx. 15 m). Changing water with a bucket gets annoying fast - then the weekly water change and care for fish and plants will soon be omitted.
  • Electricity should be connected directly next to or behind the fishtank. At best, get a (waterproof) multiple socket.
  • The tank should not be placed close to the "family memorials", as some water splashes are almost unavoidable during the cleaning work.
  • The load-bearing capacity of the floor should be observed, especially for large fishtanks (over 70 Inches). The downside of an aquarium stand in an old building must not stand straight in the middle of the floorboards between the beams. The length of the bars can be determined by tapping; the rows of nails also show the position of the bars. In addition, the feet of a stand on plastic floors can easily press into the floor. Therefore one places so-called piano coasters under the feet and brings the basin into balance.

An aquarium with water is very heavy, e.g. a tank with 50 gallons of water including gravel/sand and decoration weighs approx. 200 kg. A shaky table or a non-reinforced add-on shelf is no longer sufficient. System racks from different manufacturers usually have a clear width for common fishtank sizes. If you intend to place a tank on such a rack, you must always check the instructions for use and the technical data of this rack before purchasing the tank to ensure that the rack carries the load of the aquarium. The following overview shows the weight of water in a 24 inches long fishtank.

Filling height in inches Weight of water in kg  Total weight in kg
2 12 24
13 84 96
18 108 120

Choose the aquarium - tank types in comparison

The following pool types are available on the market:

  • All-glass fishtank (silicone-glued)
  • All glass fishtank with plastic frame
  • plexiglass fishtank
  • Anodised aluminium frame fishtank
  • Iron frame fishtank, plastic insulated
  • Chrome-plated iron fishtank
  • all-glass fishtank
  • Eternit fishtank with windscreen

I recommend an all-glass aquarium (silicone-glued or plastic frame). Here's another comparison of the different pool types:

Type of tank Advantages Drawbacks
All-glass aquarium (silicone-glued) ✓ modern, fits everywhere ✗ Heavy, edges repel easily
All glass fishtank with plastic frame ✓ Ideal fishtank type (price-performance ratio) ✗ Cheap tanks sometimes fall apart quickly
plexiglass fishtank ✓ Very light
✓ Bent moulds
✗ Plastic susceptible to scratches
Anodised aluminium frame fishtank ✓ Washers easily replaceable ✗ Leaky tanks are difficult to repair
Iron frame fishtank, plastic insulated ✓ Inexpensive ✗ Rust after a few years
✗ Not suitable for seawater
Chrome-plated iron fishtank ✓ Inexpensive
✓ Optik
✗Chrome fades quickly
✗ Rust after a few years
all-glass fishtank ✓ Handy
✓ good breeding tank
✗ Damage due to scuffing
Eternit fishtank with windscreen ✓ More robust than glass
✓ Suitable as a mini pond
✗ unwieldy
✗ Protective coating required
✗ Heavy

My recommendation: 20 gallons complete fishtank set

My recommendation: 46 gallons complete fishtank set

Consider the needs of the fish

Of course, the fish don't care what the pool looks like from the outside. It should be as spacious as possible, offer sufficient swimming space and be adapted to the species size. The following types of pools can be generally assigned:

  • Catfish and labyrinth fish generally require shallow and deep fishtanks with a large surface.
  • Tetra, Danios and most group fish want the longest possible swimming tanks, the so-called "racing tanks". They can also be deep.
  • Scalare thrive best in high tanks
  • All other species and groups are content with the tanks types offered to them. In any case, the minimum length should be observed. The wider (deeper) a pool is, the more space there is for plants and the larger the water surface: both are important factors for the health of the fish.

Select the substrate: Gravel or sand?

As plant lovers, we must, of course, attach special importance to the substrate, as the quality of the plants decides whether they grow or not. Most fish do not place particularly high demands on the bottom gravel. Often it should only be dark and not too sharp-edged. Some species require sand for grounding, in which they search for food and detritus (decayed animal and vegetable substances). After all, it should not contain metal or lime. The lime content in the substrate is easy to determine. Take a small sample and add some "lime remover" (containing hydrochloric acid). If there is foam, there is lime in the substrate. Lime itself is not harmful, but it hardens the water, which most fish don't like and plants can't stand.

Suitable substrate: Unsuitable substrate:
✓ Coarse sand of approx. 2 mm Ø
✓ Fine gravel from 3-5 mm Ø
✓ Quartz gravel
✓ Lava ground
✓ Basalt split
✓ River gravel
✗ Marble gravel (calcareous)
✗ Earth
✗ Pumice stone (floats)
✗ Dolomite quarry (calcareous)
✗ Coral gravel (calcareous)
✗ Sea sand (salty and calcareous)
✗ Shell fracture (calcareous)

How much sand/gravel does my aquarium need?

To determine the desired/correct amount of gravel/sand I recommend a gravel calculator. In general I recommend a layer of 4-6 cm sand/gravel.


My recommendation for fishtank sand:

My recommendation for fishtank gravel:

cleaning gravel

For small fishtanks up to 24 Inches, a large kitchen sieve is sufficient for cleaning, into each of which two cups of gravel/sand are placed "which is thoroughly rinsed under running water. Larger quantities of gravel are best washed outside with a garden hose in a bucket or on a large sieve. Half of the bucket is filled with gravel/sand and the hose is held to the bottom. The hose and the hand are now stirred vigorously until only clear water flows off at the top. The better the gravel/sand is washed, the less turbid the water is after the first filling.

Which fertiliser should be placed under the gravel/sand layer?

Since gravel and sand usually contain hardly any nutrients, they must be fertilized additionally in order to achieve optimum plant growth later in the aquarium. There are various ways to fertilise the soil:

  • half a inch layer of coarse, unwashed construction sand. This has the disadvantage that this soil layer becomes clogged after 1-2 years, so that the substrate has to be renewed. The gravel / sand layer (2 inches) comes over fertiliser-sand layer.
  • Mix gravel with a substrate fertiliser and lay the first layer approx. 1 inch high on the pool bottom. Above it comes the gravel/sand layer (2 inches).
  • Add fertiliser balls every 3-4 Inches into the gravel/sand layer. This method can also be easily applied to tanks that are already in operation.

Technology and accessories for aquariums

Besides the substrate and the choice of the correct tank type, the choice of the right technology and the right accessories plays an essential role in setting up a new aquarium. The following covers everything from lamps, internal and external filters to heating thermostats.

The choice of aquarium-light: LED, T5 or T8?

Fluorescent lights - T5 and T8: Their luminosity is generally strongly dependent on the reflector. Deal would be a mirrored lightbox or at least one that's white inside. If only a dark light box inside is available, you can easily glue aluminium foil into it. This improves luminous efficacy by up to 50%. The burning time of the fluorescent tube is approx. 12,000 hours. After just one year, however, the luminosity decreases continuously. After one and a half to two years the luminosity is only about 80%. Therefore, the fluorescent tubes should be replaced after two years at the latest. In general, T5 consumes significantly more electricity than T8, but is much cheaper to buy.

LED: The LED continues its triumphant advance in aquaristics. Although the acquisition costs are sometimes six times as high, it also easily burns six times as long. In my subjective opinion, however, it produces a much more beautiful and vivid colour picture and often delights with additional additions such as a day/night change, dimmability or colour change.

fishtank aquarium light  watts number of tubes
lenght in inches gallons length in inches

Heating thermostat: an overview of the various heating systems

Every living being needs food and warmth. Tropical fish need more warmth than our native ones, because their organism is adapted to the tropical heat conditions. For most of the tropical species there is a central area where everyone feels comfortable. This is at 24-26°C; native fish are best kept at 12-20°C; goldfish at 18-22°C; cold-water fish from mountain streams tolerate lower temperatures of 8-12°C.  Too low temperatures harm the animals more than too high temperatures. However, the latter often impairs the life span, fertility and colourfulness of the ornamental fish. When selecting fish in a community aquarium, the temperature should therefore definitely be taken into account as the interface and a constant temperature should always be guaranteed. Fortunately, there are heating thermostats that make all our lives easier.

  • The rod heater: The aquarium heater is also known as a sand-filled glass tube with a heating coil. These rod heaters are available in different wattages of 10-500 watts. The advantage of these heaters is their low price. The disadvantage is the relatively high surface temperatures with a low radiator surface.
  • The controller heater: The most commonly used heater is a combined controller with heater in a glass tube. Most devices are to be used "upright". Well-sealed equipment is sold in Europe. In the USA and Japan, for example, devices are also offered that have only one cap with a control device made of hard plastic through which water can quickly penetrate. The heaters are durable and have an almost unlimited service life - but the glass tube must not be knocked against the edge of the pool. A fluctuation range of 1-2°C is not harmful to the inhabitants of the pool.
  • Underfloor heating: Laying heating cables in the underfloor is a well-known method in terraristics. Of course, this variant is only recommended for new installations. The bottom heater is attached to the base plate with suction cups. The aquarium gravel is layered directly above it.
  • External filter with control heater: Same principle as the control heater, except that it is already integrated in the external filter.

How many watts of heating power does my control heater need? In heated rooms, the output of the heater should be 1/3 - 1/2 watt per litre of pool.

The aquarium filtration: external or internal filters?

Which filter size for my aquarium?
The filter size will primarily have to be adapted to the size of the fishtank, the number of ornamental fish and thus the amount of dirt produced. In general, the bigger the better. However, this is not the case for planted aquariums. These should be filtered rather weakly and for it only very sparingly with fish to be occupied!

The filter performance should be based on the same criteria, but first and foremost on the volume of the tank. A weakly occupied 100 litre aquarium can easily manage with a filter of weaker performance than a 24 gallons tank with a strong population. As a rule of thumb, the filter volume should be as large as possible and the capacity per hour should correspond to about half the tank volume.

Table: Filter capacity for 100 litres aquariums

tank occupation 1 inches of fish on x gallons of water Filter capacity per hour Filter volume minimum 
13 gallons
26 gallons
40 gallons
more than 50 gallons
1 Pint
2 Pint
4 Pint
8 Pint

Filter suggestions:

For small (breeding) fishtanks up to 20 gallons: foam cartridge filters or plastic corner filters.

My recommendation

Up to 80 gallons fishtanks (also 45-46 gallons and 56-60 gallons): Centrifugal pump top filter with 80 gallons of capacity. External filters or biofilters installed by the tank manufacturer are also welcome.

My recommendation: 

For medium-sized fishtanks up to 40 gallons: submersible centrifugal pump, centrifugal pump top filter or foam cartridge filter.

My recommendation:

For large fishtanks from 80 gallons: Centrifugal pump top filter with 135 gallons capacity and above or a biofilter built into the tank. Also practical: filter tanks!

My recommendation: 

Decoration: Which stones and which wood for the fishtank?

When you know which fish you want to keep, it is easy to choose the decoration for the tank. Besides stones, roots, wood, cork bark, slate and also plastic terraces, which can be bought ready, plants are the main decoration. An exception are fishtanks for herbivorous fish and African cichlids. Natural materials are particularly suitable as decoration fabrics:


  • basalt
  • porphyry
  • granite
  • mottled sandstone (non-calcareous)
  • lava stone
  • shales
  • stone wood
  • flowerpot

Unsuitable stones are: 

  • marble
  • limestone
  • dolomite


  • Roots from the moor (bog wood)
  • mangrove wood
  • Tonkingbars for imitation of reed thicket
  • bamboo sticks
  • coconut husks

Unsuitable wood: 

  • coniferous
  • Wood from bushes

Also unsuitable for decoration: 

  • All types of metal

Decoration materials can also be collected outdoors. Particularly beautifully coloured pebbles from Sunday excursions are not only cheap, they are also a lasting memory. In the brooks of our low mountain ranges, in gravel pits or quarries you will find all kinds of useful material. Knotty burl wood from the stream may look very bizarre, but is usually unsuitable as decoration, since the watered and sometimes already faded in the warm aquarium water quickly rots and soon molds. Moorkien wood, on the other hand, has been in peat, i.e. in very acid soil, for years under airtight conditions. Flocks of rot are no longer contained in such wood.

Before use, such bog wood can be boiled in a pot to allow the air contained in it to escape. Larger pieces can also be rinsed off in the shower with hot water. In addition, the wood is weighted down with stones or tied down with cable ties so that it holds its position.

Setting up the fishtank - step by step:

We have already gone through the individual steps in the previous chapters. In summary, the essential points are gone through here again and listed in the usual order:

  1. Choose the right location
  2. Chose the fish you want to keep
  3. Clean tank and check for leaks
  4. Glue the back wall or use a 3D back wall as required.
  5. Place a polystyrene plate (1 cm thick) or a felt plate under the aquarium.
  6. If a heating plate is used, it is placed under the styrofoam/felt plate
  7. clean the gravel/sand
  8. mix lower gravel/sand layer with substrate fertiliser
  9. Pour clean gravel/sand over it
  10. Choose the decoration
  11. Fill a quarter of the fishtank with water. A plate can be placed on the substrate to prevent the substrate from being stirred up. You can also first plant the plants and then add the water.
  12. plants: For a new aquarium it is best to use fast-growing plants such as hygrophila, Vallisneria, water stars and sword plants. Plants should not be saved, as few plants cannot cope with the biological imbalance of a newly established fishtanks.
  13. Install heater or control heater. If no thermal filter or heating mat is used. The control heater is fixed in a rear corner with suction cups
  14. Installing the filter
  15. Fill in the total amount of water
  16. Start up filters and heaters
  17. Activate the lighting and adjust it to the lighting times with a timer: 8-10 hours a day are recommended during the running-in phase.
  18. Check water values
  19. If present, "contaminate" the tank with filter media from a already run-in aquarium. This can significantly reduce the running-in time.

The first fish and snails - how to acclimatize living beings?

After two to three weeks the first snails can be inserted and after four to five weeks the first fish. Here you can say: the longer you wait, the safer it is for the fish. Useful soil bacteria, which also develop in filter media, need several weeks to be able to degrade nitrogen-containing products that the fish excrete. The plastic bag by bringing the fish home is placed on the water surface for 5 minutes so that the fish get used to the water temperature. Then about half a pint of water from the fishtank is dripped into the bag every 5 minutes. Water is added about 6-8 times, so this process should take about 40 minutes. The new aquarium inhabitants can then be released into the tank water.

Setting up a Fishtank – How to start a aquarium

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