How to Set Up a Tropical Fish Tank

Written By Lewis German  |  Tropical Fish  |  0 Comments

Before purchasing a tropical fish tank and getting your hands wet, there are some important first steps you need to take.

These first steps are the planning and preparation for your new tank. 

There are several questions you need to ask yourself that will help you to decide whether or not it would be suitable for you to take on a tropical aquarium.

What to consider when getting a tropical fish tank


The first stage is research, something which you are doing now by reading this article. You need to find out what goes into setting up and maintaining a tropical tank, what sorts of things it involves and find out what you may or may not be comfortable with.

The best way to find out what’s best for you is to research a specific fish that you like. Go to your local fish store or look online at different tropical fishes, ask about them and research them.

Find a fish or group of fishes that you particularly like and would want to keep, and then research what goes into looking after them. Look at:

  • Their diet
  • Tank size
  • Aggression levels
  • Water parameters
  • Whether you can you provide the right environment for this fish

Once you have a fish you definitely want to keep that sounds ideal, purchase and build your tank around this fish, and set up the environment with it in mind.

Alternatively, you may also do the reverse. You may have acquired a tank from someone, and will need to do research to find what fish are able to live in it.


Finding out what is affordable to you is also important, it is no secret that fishkeeping can be a very expensive hobby if you allow it to be.

Upfront costs of equipment, running costs, electricity, food; all these things add up, so it is a good idea to find out what you can afford and find the best options within your means.

For example, many of the larger pufferfish or oddball species can be very expensive animals to keep. They often require large tanks, big filtration equipment and are very expensive to feed.

Something like a Guppy however, is comparatively very cheap. They are small, can live in smaller setups with smaller filtration systems, eat flake food and have relatively low running costs.

Find out what works best for you, and balance it with what you want to keep. You don’t want to be running into debt because of your fish.

Fishkeeping is a hobby that should be enjoyed, not something that should cause you extra financial issues.

Finding where you get your equipment from can also help, as while you can spend hundreds on a brand new tank setup, you may be able to find the same tank second hand for very cheap, or even for free in some cases!

Fishkeeping is as expensive as you make it.


The next thing you need to consider is where you are going to put the tank. 

  • Do you have enough space for the tank to go?
  • Can this space support the weight of the tank?
  • Are there access to electrical sockets?
  • Is it a safe place for water to be?

Some planning and thinking is required before you go purchase a 100 gallon aquarium and then realise you have nowhere to put it.

There are also some spaces within a house that are not usable for reasons you may not consider at first.

Here are a list of spaces in a house or building that are not ideal for a fish tank, as well as the reasons why they are bad:

  • Next to a door (fish will become stressed from opening and closing doors).
  • In a conservatory (fish will be subject to major temperature fluctuations).
  • In the attic (fish will be subject to extremely hot temperatures/ceiling may not support weight).
  • Above a stairway (could fall while performing maintenance).
  • In the kitchen (fumes and gases will dissolve into the tank).
  • In the bathroom (fumes, gases and heat).

Alternatively, here are some good spaces to put an aquarium:

  • Bedrooms
  • Living rooms
  • Dining rooms
  • Well insulated shed or garage
  • Basement
  • Hallways with very little traffic

What equipment do you need for a tropical fish tank?

Equipment will vary from person to person, as each setup may require different levels of filtration and tech. Some systems are very “low tech” and have comparatively minimal equipment running on them. Others are “high tech” and have lots of fancy machinery, tools and electronics keeping things running smoothly.

For all aquariums, you need a filter, as the nature of a fish tank means you are containing waste producing animals in an enclosed space. This waste (fish food and resulting faeces) produces ammonia, which is highly poisonous and will kill your fish in high levels.

A filter will help remove this ammonia and convert it into a less toxic form (nitrate) which can be removed by live plants or through a water change.

Filters also help to get oxygen to your fish, as they disturb the surface of the water and allow gas to diffuse. (Yes! Fish breathe oxygen, like all animals).

It is safe to say that without a filter, your fish will not live very long healthy lives.

For tropical fish, it is also advised that you get an aquarium heater too, as it will allow you to better control the temperature in your tank and set an ideal range for your fish. Room temperature (20C/68F) does not cut it for most tropical fish, who prefer warmer temps.

If you decide to have live plants in your aquarium (which we typically advise as they make your life as a fishkeeper much easier), then you will also need a good lighting system, with strong LEDs or T bulbs.

Most fish tanks however, are just fine with the standard filter and heater, with regular water changes.

As you get more into the hobby, you may find more equipment you want to run, such as CO2 diffusers, skimmers, sumps, dosers and all different types of “non essential” tools that do some very interesting things.

Water treatment for tropical fish tanks

People often think of water as a clean, featureless fluid, with not that much interesting about it. However, this couldn’t be further from the truth.

Water is most often diluted with all different types of materials, nutrients, tiny creatures and minerals, which give it different chemical properties, affecting things like pH, calcium levels and water clarity.

No two bodies of water are the same, so the water from your tap can sometimes be very different from the water in the Amazon river or Lake Malawi.

This is why we need to understand water by testing it with various tools and kits.

We need information on the pH level, hardness level, ammonia level, nitrite and nitrate level.

When we use tap water for our fish, we sometimes need to condition it to be more like the natural waters the fish is used to in its native habitat. This can be done by adjusting the pH and hardness using buffers, plant materials, minerals or chemicals.

We also need to remove harmful materials found in tap water, like heavy metals. Chlorine, chloramine and a range of other nasty things that could harm your fish.

We do this using a dechlorinator; either a chemical or carbon filtration unit, which can remove these substances.

Understand that while you can drink tap water with relatively no issues, your fish are not the same as you, and will receive negative effects from being exposed to chlorine and other toxins.

We dechlorinate our water every time we do a water change and refill the tank with new, clean water.

The Nitrogen Cycle

The nitrogen cycle is extremely important to understand, and everyone should have a good grasp of it before they decide to keep fish. It is key to success in aquarium keeping.

Infographic of the Nitrogen Cycle, covering feeding, ammonia and waste matter

Stage 1

All animals live their lives consuming food and excreting it as waste material (faeces). This waste is filled with decomposing organic matter and bacterias, which over time, release ammonia.

This is the first stage in the nitrogen cycle. You feed your fish, it consumes and digests the food, and a few hours later, it defecates, releasing ammonia into the tank.

Ammonia (NH3) is very toxic, and an over exposure to it will kill any animal.

It is particularly dangerous to fish as it dilutes the water quickly, which is absorbed by the fish and burns the skin and gills, causing toxic shock to organs and stopping essential bodily functions, soon leading to death.

When testing your water, you want to see an ammonia level as close to 0 ppm as possible, as any level of it within the tank will cause irritation and damage to your tank inhabitants.

To remove it, we use a special type of naturally occurring bacteria, called “nitrifying bacteria” which consumes and converts ammonia into a less toxic state, called nitrite.

Stage 2

The second stage of the nitrogen cycle is when nitrites (NO2) are made. This is not quite as harmful as ammonia, but is still very toxic nonetheless. Readings should still be at 0 ppm to be safe for fish.

The bacteria that feed on ammonia and convert it to nitrites take some time to grow, (around two weeks) before they can effectively work. This bacteria grows all over the tank and in the substrate, but mostly in the filter, where there is plenty of passing nutrients and oxygen.

To successfully complete the nitrogen cycle, nitrates must also be converted into yet another less harmful toxin.

Stage 3

The third stage of the nitrogen cycle is when another bacteria (Nitrobacter) grows and feeds on the nitrites, converting them to less harmful nitrates.

Nitrates (NO3) is the final stage of the nitrogen cycle and is the least harmful state that animal waste can be in before it is then consumed by plants.

If you detect nitrates in your tank, it means that your filter and tank is fully cycled and is working effectively. Nitrates however, are still toxic in high levels, although fish can tolerate a low level of nitrates for a time, an ideal is keeping the level at less than 5 ppm.

Nitrates must then be removed from the tank through a water change, or they can be consumed by plants.

Plants leech nitrates directly from the water, keeping it clean, which is why we always recommend keeping live plants if you can. They do, however, have their limits and you will still occasionally need to water change, just not as frequently as you would if there were no plants at all.

The whole nitrogen cycle process takes around 1 – 3 weeks to finish. Once you start to see nitrates developing in your tank, it is safe for fish to go in.

Another 3 months to a year later, and the tank will be “mature” and will be very chemically stable, often requiring less maintenance and being a safer environment for fish.

Here is a great video from the team at Fluval that helps you through the process.

What decoration should you put in a tropical fish tank?

How you want the tank to look is really up to you, but most fish will really appreciate having multiple places to hide where they can get out of sight of each other and you.

Having the option to get away and feel safe makes fish feel secure and ironically, they will actually be more confident and be out more often if you provide them with hides, than they would be if the tank was featureless.

Certain decorations can have specific effects on your tank, such as driftwood, which leaks tannins, staining your water brown and reducing the pH. Limestone will slowly dissolve into the water and raise the pH.

These decorations which have an effect on the water chemistry can be beneficial or detrimental depending on what you want for your tank. Of course, these are still usable in any setup, they just need treating first to remove their active properties.

Boiling driftwood for a week or so before adding it to your tank will leech out most of the tannins.

Other items like smooth pebbles, igneous rocks, terracotta and sand usually have no effects on the water and can be used in any setup without needing to be prepared and treated first.

Live plants

As mentioned, live plants will leech harmful toxins from the water which are produced by your fish. Plants are part of the natural ecosystem in your tank, and do a great job of helping to maintain it.

There are hundreds of species of plants out there, that all grow in different ways and do different things. 

Contrary to the popular belief that plants are hard to keep, they are actually very easy to keep alive. In fact, it is easier to keep a fish tank with live plants, than it is to keep one without!

This is because of the many benefits plants bring, such as their filtration capabilities, oxygen production and ability to house infusoria, which are vital components of a well functioning aquatic ecosystem.

You will however, need a strong light which they can grow under. Most aquarium LED lights or T bulbs will work just fine for most plant species, and will allow you to successfully keep a beautiful, self-sufficient, planted tank, if you want to go down that road.

Introducing tropical fish to a tank

Once your tank is running, has cycled for around a week or so and is testing clear, then you can add fish. It is best to do this in increments, with only a couple fish at a time, so as to not overload the system.

Every Time something changes in a fish tank, the ecosystem has to balance itself to keep up, and suddenly adding 100 fish to a new system will quickly cause it to “crash”, which will kill everything.

Over the span of a month, slowly add fish a couple at a time, allowing the filter to keep up with the new additions.

Each time you add new fish, acclimate them slowly into the tank using a drip method, slowly mixing your water with the water in the bag. 

Do this for around 30 minutes before adding your fish, and make sure to never add the store’s bag water to your tank, as it often contains trace amounts of copper and high nitrates which are bad for your aquarium.

Once they are added, allow them to destress, turn off the lights and leave them to their own devices for the next day.

After a few days to a week, they will have fully settled in and you will have successfully set up your new tropical tank.