Setting Up a Fish Tank: A Beginner's Guide

LAST UPDATED 13 March 2023

This article is written by Pet Circle veterinarian, Dr Emilee Lay BSc (Vet) Hons BVSc and edited by Dr Nicole Wynne Bsc BVMS MANZCVS (Unusual Pets)

Fish keeping is an exciting hobby and can be quite relaxing once you have everything you need to set up and maintain it. But there is quite a bit you need to know and have on hand. Gone are the days of buying a fish on the fly and adding it into a tank of water. Fish Keeping can be as simple or as intricate as you desire but there are some things to bear in mind. Read on to find out what you need to set up your tank. 

1. What Kind of Fish Do You Want To Keep?
2. Tropical Fish vs Goldfish
3. Where To Put Your Tank
4. Planted vs Non-Planted Tanks
5. Choosing a Substrate
6. Decorations
7. Aquarium Filters
8. Heaters
9. Air Pumps and Accessories
10. Adding Water and Cycling Your Tank
11. Choosing and Adding Fish
12. Quarantining Your Fish

What Kind of Fish Do You Want To Keep?

A huge range of fish can be kept in a home aquarium. Broadly speaking, fish can be divided into Marine and Freshwater varieties. In the freshwater category, you then have tropical fish and coldwater fish such as Goldfish. Knowing what kind of fish you wish to keep will influence a lot of the decisions you make when setting up your tank. In the interests of keeping things simple, this guide will go through keeping Freshwater Fish. 

Keeping Tropical Fish vs Goldfish

There are many pros and cons to consider when choosing between tropical and goldfish. Some popular tropical fish include discus, guppies, tetras, mollies, loaches, cichlids and bettas. They come in a variety of breeds, sizes, and colours - meaning you can have a varied, vibrant aquarium at home.  Another benefit of tropical fish is that compared to goldfish, most of them can be kept in much smaller aquariums. The rule of thumb when it comes to stocking a tank for tropical fish is approximately 1 inch of fish (in length) per gallon OR 2.5cm of fish to 3.8L of water. If you have limited space at home for a fish tank, they can be a great starter even though they require slightly more work to set up. For example, Bettas can be kept happily in a 10-15L setup. Unlike goldfish, tropical fish do require a heater and are more sensitive to water quality issues. 

On the other hand, Goldfish are quite popular as starter fish. However, despite being touted as great starter fish, they do require a larger tank size long term in order to thrive. A single goldfish needs a minimum of 60-80L. Due to their robust nature, and sometimes aggressive tendencies, they are best kept with their own species, with fancy tailed goldfish such as Ranchus, Orandas and Fantails being kept separate from single tailed goldfish such as Comets and Shunbunkins. This prevents tail and fin damage from the faster, nimbler single tailed fish.

 There are common misconceptions that they can be kept in small tanks or small bowls, and will grow to the size of the tank. Unfortunately this is not the case. Goldfish kept in less than ideal conditions will have a greatly reduced lifespan, stunted growth and abnormal development - they will continue to grow regardless of the size of the tank/bowl but will grow at a reduced rate. Goldfish generate quite a bit of waste and so large tanks, frequent water changes, and a powerful filter are musts to have your fish thrive. Goldfish are popular for their gorgeous colouration and longevity, and optimal conditions will bring out the best in their vibrant colours. Do be aware that fancy goldfish are less hardy than their less flamboyant counterparts, and so require more diligent care.

Fish tanks these days occasionally come as ALL-IN-ONE kits which include almost everything you need to get started. 

Where To Place Your Fish Tank

Ideally, you want to set up your tank in an area of the home that doesn’t get too much direct sunlight. Excess sunlight can cause algal blooms and heat the tank water (which may not be ideal for the species of fish you are keeping). Also, consider the distance to a power point and water source. Fish tanks need at least weekly maintenance and water changes. Filters, heaters, air stones, and light all require a power source. 

Next to consider is the size of your tank, not only in terms of the space it will take up, but the weight it will be. Remember that 1L of water weighs 1kg! So it can easily add up once substrate, decorations, cabinetry, and accessories are added in.

Planted vs Non-Planted Tanks

Creating a visually appealing tank is not only great for the eyes but fantastic for your fish. Fish also require mental and environmental enrichment. Before deciding on your tank consider if you want live plants because that will govern your purchasing decisions. Aquascaping, also known as underwater gardening, is an artform that focuses on imitating nature in your aquarium. These can be low tech in nature, not requiring carbon dioxide injections into the water and utilising hardier aquatic plants, or full blown high tech setups with artificial carbon dioxide injections, high intensity lighting and supplementation. When it comes to the styles of aquascaping the main categories are Takashi Amano Nature Style, Iwagumi Rock Style, and the Classic Dutch Style. Look them up for a stunning visual treat! 

Planted tanks require a bit more fine-tuning. Regular pruning and care with lighting is a must to help them thrive. When cleaning tanks take care not to disturb the gravel which can result in more waste building up. Research is needed into the types of plants that can be used in your setup, but live plants do provide many benefits. Asides from a natural environment for your fish, they can also help break down waste by using it as fertiliser. 

Although planted setups do not have to be complicated, it’s important to check whether the type of fish you wish to keep is suitable for those setups. Goldfish in particular are vegetarians and love nibbling on plants and uprooting them. On the other hand, tropical fish such as tetras and guppies thrive with plants and enjoy shoaling and swimming amongst them. Easy starter plants that are quite sturdy include Anubias, Amazon Swords, Crypts, and Java Ferns. 

Artificial plants lack the visual benefits of live plants, but artificial plants now come in realistic silk and plastic forms and can be very close to the real thing. Although fake plants of low quality can be unappealing, higher quality designs and colours are now readily available. They require minimal, if any, maintenance and can be kept with any fish from your vegetable loving goldfish to your active African cichlids. They can be rearranged easily, making cleaning the tank nice and simple. 

Choosing a Substrate

Substrate comes in a range of options from river rocks, natural gravel to sand, and even aquasoil for planted tanks. When choosing a substrate don’t forget to consider the type of environment you wish to create, as well as the requirements for your fish. Other considerations include particle size, colour, and water parameters.

Larger-sized substrate allows for more waste to build up in your tank which can foul the water. When using sand or small, finer particles of substrate it can make cleaning difficult or become compacted generating hydrogen sulfide which is extremely toxic to fish.

Substrate comes in many colours as well. You may wish to pick a colour that enhances the colours of your fish or as a natural backdrop for an aquascaped tank. Pick darker colours to pair with lighter fish and vice versa. If you intend to commit to a planted tank consider a nutrient rich substrate suitable for plants.

Don’t forget to consider the behaviour of the fish you wish to keep. Goldfish generate quite a bit of waste and are sometimes kept in bare-bottomed tanks for ease of cleaning. However, they do enjoy sifting through gravel. If you intend to have Goldfish with substrate pick a large or very fine gravel to minimise the risk of choking. Cichlids thrive in waters with a higher pH. Using sand/coral-based substrate can help buffer the water and create their preferred environment.

Prior to adding any substrate to your tanks, rinse it thoroughly in water until the water turns clear. Substrate that has been prewashed can become cloudy as it disintegrates during transport, so a thorough cleaning is a must to keep your water clear.  

Choosing Decorations for Your Tank

When picking decorations for your tank, whether that be large rocks, artificial statues or formations, vines, or driftwood, it's important to be mindful of their size. Decorations will take up space and reduce the areas available for swimming. Make sure that they are easy to clean and move in your tank. 

Driftwood occasionally needs soaking or “curing” in water for a few days to ensure it sinks in your tank. Curing driftwood also helps to release tannins which can cause your water to become cloudy or discoloured. Although tannins are not harmful to your fish they can be unappealing and can lower your tank pH over time. 

Be mindful of the weight these rocks will add to your aquarium. If you are using large rocks as centre pieces, ensure you have a thick layer of substrate underneath to reduce the risk of cracking or breaking your aquarium. Double-check that the rocks you select (and there is quite the range) are inert in water. Some rocks contain calcium carbonate which can alter the hardness and pH of your aquarium water - which is perfect for some fish like Cichlids. 

If you decide to add lighting to your tank make sure to have it on a timer - fish, like humans, need sleep! Lights shouldn’t be on longer than 8-10 hours. Excessive light can be stressful and also contribute to algal blooms in your tank. Many aquarium lights come as LEDs, and can be clipped onto the top of your aquarium or side. Planted tanks may require a different spectrum of light to enhance plant growth. 


Shop All Fish Decorations Now

Aquarium Filters

 Tanks rapidly build up waste and toxins when left unattended. Filters quite literally filter out debris and contribute to breaking down waste, drastically reducing the maintenance of your fish tank. 

There are 3 categories of filters:

  • Mechanical filter: A filter that removes particles from the water. This is usually the mesh/sponge component within a tank filter.
  • Biological filter: This is the most confusing of all of the types of filters as this actually refers to the bacterial population of the tank that helps to break down fish waste, so not actually a machine or a machine part!
  • Chemical filter: uses chemical reactions to help absorb harmful particles 

Filters that combine at least two of the above are ideal. Filters available on the market include canisters, hang-on, sponge and internal filters. When choosing a filter take into account the volume of your tank, the type of fish you are keeping, and any space restrictions you may have. 

Check out our article about Everything You Need to Know About Filters to find out more.

Shop All Fish Filters and Media

Do I Need a Heater For My Fish Tank?

Heaters are essential for keeping tropical fish. Heaters come in a variety of wattages depending on the size of your tank. Some heaters come at a preset temperature, whilst others can be set manually within a certain range. Every tropical fish has a preferred temperature range and this is important to consider when selecting your fish and setting up your tank. Goldfish can also benefit from a heater - although this isn’t necessary. Fancy-type goldfish are more likely to thrive in slightly warmer temperatures (up to 20C). 

Fish do not cope with sudden temperature changes - ensure you have a backup heater just in case! Heaters should be placed closest to the filter outlet to allow even heating of the water throughout the tank. Make sure to have a thermometer in your tank to monitor the temperature of your water. Thermometers can be as simple as a heat-changing sticker through to digital thermometers. For fish who are sensitive to temperatures, the latter may be preferable. 

Air Pumps and Other Fish Tank Accessories

Although filters can help to oxygenate the water, air pumps are far more efficient. Air pumps provide oxygen for your tank and help to improve water circulation. Oxygen deprivation can be detrimental to your fish, and tropical tanks, larger tanks, or heavily stocked tanks need supplemental oxygenation. If you live in an area prone to power outages, having a battery-powered backup air pump is a must. Air pumps are generally similar across the range with different sizes to accommodate different tank sizes.

Air pumps require an air stone (which helps to reduce the size of the bubbles coming from the air pump), an air line (a piece of plastic tube to connect it to the air stone), a flow regulator (these are optional and are ideal for air pumps which don’t allow you to regulate the flow manually), and most importantly, a check valve. Check valves are essential to preventing your air pump from suctioning water OUT of the tank. Air pumps placed below the level of the airtube or airstone are at risk of siphoning water out of the tank. Check valves only allow air/water to move in one direction. 

Other must-have fish tank accessories include a gravel vacuum (to help easily siphon up waste in your tank during water changes), a fish net to help move your fish safely from your tank as needed, an algae scraper/glass cleaner to keep your tank clean and filter brushes to maintain your filter tubes at home. Read our Fish Tank Maintenance 101 for more information. 


Adding Water and Cycling Your Fish Tank

Even though your tank may be all setup and ready to go, it is not quite ready yet! When adding water to your tank, use a shallow bowl or plastic container to reduce the force of the flow and minimize agitating up your substrate. Once your tank is full, and you've decorated it accordingly, its time to turn on all your equipment and make sure it is working. There might be a tonne of air bubbles initially, but these will dissolve as your tank settles. Make sure to add a water conditioner to your tank to make the tap water safe for your fish. 

Now that you've added water it's time to cycle your tank. Unfortunately, you cannot immediately add fish to your aquarium - it needs to be completely cycled before you can safely add fish. Think of an aquarium as an established closed system.

Cycling your fish tank involves kick-starting and maintaining appropriate systems of beneficial bacteria that can break down fish waste or ammonia into less toxic and more manageable forms. A little bit more patience whilst cycling your tank will set you up for success. It can take up to 4-6 weeks for a tank to be completely cycled. Don’t skip or rush this process. Chemical additives claiming to kick start and maintain your aquarium cycle, bypassing the normal cycling process, are not 100% and can be risky for your fish.

Read our article on a guide to Cycling your Fish Tank for more details.

Adding Fish To Your Tank

You can introduce your fish to your tank once your tank has been fully cycled. By now you should have already made a decision as to what kind of setup and fish you would like to keep. Check out your local aquariums and pet stores when selecting your fish. 

Before purchasing your fish, observe them in the tank. Some questions to ask yourself include:

  • Are they bright and alert? 
  • Are they interacting with their tank and surroundings? 
  • Are there any obvious injuries to their fins, tails, and eyes?
  • Do they have a normal shape and spine (this is particularly important for some of the fancy goldfish breeds)? 
  • Can they swim normally? Warning signs are fish that float at the surface or sink to the bottom.
  • Do their scales look healthy, or are there any abnormal lesions or fuzzy material on them?  
  • Are their tank mates happy and healthy?

Once you’ve picked out your fish, transport them carefully home - they will be placed in a bag filled with some of their tank water and fresh oxygen. Have a box in your car to minimize the bag rolling around. 

You will need to acclimatize your fish to your tank water prior to adding them in. This is a simple process. First turn off any tank lights, as this can be quite stressful for fish in an unfamiliar environment. Float your fish in your tank for up to 20 minutes, after which point open the bag slightly and pour some of your tank water into the bag and let it sit for another 5 - 10 minutes before adding a little bit more of your tank water. After another 5-10 minutes you can use a net to carefully scoop your fish out of the bag and place them into your tank. Never pour the bag water into your tank as it can introduce disease to your tank water. 

Quarantining New Fish

If you already have pre-existing fish in your tank, you may want to consider having a quarantine setup before adding new fish. This can be as simple as a plastic tub or a smaller tank filled with cycled water and a sponge filter. You can use filter media from your established cycled tank to kick-start the cycling in your quarantine tank in a short period of time.

You can worm and treat your fish for any signs of disease prior to adding them into the main tank. Quarantine periods are generally 2-4 weeks. Although quarantining new fish isn’t a must, it reduces the risk of introducing new diseases or parasites into your tank. 

Quarantine tanks are fantastic as hospital tanks, should you notice any of your fish are unwell.

Further Reading

Want to read more? Check out our other articles:

How to Cycle Your Fish Tank

Fish Tank Maintenance and Cleaning 101

Choosing a Filter for Your Tank

Common Aquarium Problems and How to Solve Them

Feeding Your Fish

Shop All Fish Supplies Now

We're Australia's #1 rated and largest online pet shop for pet food and supplies!