Aquarium Setup

Aquariums are a low-maintenance, allergy-free, and elegant approach to keeping pets. Before you run out and buy a bag of fish, however, it’s important to understand and set up the tank and its equipment. Currently there are a wide variety of kits available commercially for the beginner aquarist (a person that maintains an aquarium), and most will include the tank, lid, and light, a heater and thermometer, and a filter with or without an air pump.

Tank Size

Although it is tempting to buy a small tank for your first aquarium, I don’t recommend starting with anything smaller than 20 gallons. A larger tank size will tend to dilute any minor changes in water quality and temperature, and in the end there is a lot of money to be saved in replacement fish. A small tank will magnify every fluctuation and can be frustrating to even the most experienced aquarists.


In most areas, tap water can be used for a freshwater aquarium with minimal treatment. The main concern is chlorination: chlorine is often added to water to kill germs, and it will also kill fish. There are many commercial products available that can be added to tap water to remove the chlorine. If you are patient, chlorine will evaporate from water left in an open-topped container after about a day. However, there are occasionally other chemicals or minerals present in tap water that can be harmful to fish, especially more sensitive species. For example, old copper pipes can sometimes lead to heavy metal toxicity in fish. If you are concerned, most fish supply stores can test your water for a variety of contaminants if you bring in a sample. Specially pre-treated water (such as reverse osmosis water) can also be purchased, but this is less practical for larger tanks, as you will need to add water frequently as it evaporates and when changing the water (a good rule is to change about 10% every 2 weeks).

Air Pump

The main purpose of an air pump is to ensure movement of the water – usually through a filter system – rather than to force oxygen into the water. The bubbles help draw water through a filtration system and also break up surface tension. Most oxygenation occurs at the water’s surface, and if there is no movement, a thin film of protein residue will develop and prevent normal gas exchange. Not all filters require an air pump to promote water movement; some pump the water directly.


There are three types of filtration in a fish tank: mechanical, chemical, and biological. Mechanical filtration is the removal of particles and solid debris from the water, and is usually achieved by forcing water through a sponge, wad of cotton, or other media that needs to be changes periodically. Chemical filtration removes dissolved gases and toxins. This is usually accomplished with activated carbon particles. Biological filtration refers to the breakdown of waste products (from fish or plants) into non-toxic components by bacteria. This component of filtration is potentially the most important to ensure water quality remains stable over time.

When choosing a filtering device, consider which of these filtration types is being incorporated. For example, an under-gravel filter provides excellent biological filtration, as oxygenated water is passed through the bacteria-filled gravel. However, additional mechanical and chemical filtration might be needed, in the form of an internal corner filter (which generally provides no biological filtration). “HOT” or “Hang On the Tank” filters are very popular for beginner aquariums; they incorporate all three forms of filtration to some degree, they do not require an air pump, and they are fairly easy to clean and maintain.

Temperature and Lighting

Daily variations in temperature can provide a lot of stress for fish, and dramatically shorten their lifespan. The preferred temperature for your fish might depend on species, but in a mixed-species tank, keep in mind that a slightly cooler temperature is usually less stressful than a warmer one. Consider placing your aquarium away from windows and heat sources, and use a submersible heater to regulate temperature. Sunlight can also encourage excessive algae growth. Most aquarium kits include a plastic lid with a fitting for a fluorescent or incandescent light. Fluorescent tank lights are more efficient than incandescent bulbs and produce less heat.

Gravel and Decorations

Gravel substrate and wood, plastic, stone or ceramic decorations are available from most pet shops, and these are the safest for beginners to add to any tank. Sometimes homemade or found decorations (such as seashells) can dissolve in the aquarium environment and some may even become toxic to the fish. Everything should be rinsed thoroughly with clean water before being added to the tank (never use bleach or other harsh cleaners).

Gravel is generally added at one pound per gallon, and the preferred type varies by fish species and the look the aquarist is trying to achieve. In general, fish are less concerned about colour than they are about the size and texture of the gravel, or the availability of hiding spots among decorations.

Cycling the Tank

Once the tank is set up and filled with water, you can begin the cycling process. This is a sort of “seasoning” process that allows time for bacteria to set up shop and start processing waste – in other words, the biological filtration. This is usually done with a few hardy fish for days to weeks. Ask your local pet shop about the hardiest species from the list you eventually intend to keep – goldfish are not ideal for cycling unless you want to keep them in the long term. This is also a good time to take a water sample into the local pet store and have it tested – they will be able to tell you if your water quality is suitable for fish
By Jen Perret – writer