How to set up a fish tank for the first time

How to set up a fish tank for the first time! This is not as difficult as you might think if you follow our simple guide. It is a well known fact that aquariums are relaxing. If you have never set a fish tank up before it can seem a little daunting but it really is easy. In just a few simple steps, you can become a fish keeper!


The first step is to choose a tank. Things to consider are…

  • What type of fish you would like to keep?
  • Where is the tank going to go?
  • What is your budget?

Choose the right type of aquarium for the fish you intend to keep. Larger tanks are easier to maintain and have more stable water chemistry. Small tanks can look gorgeous if you choose fish or shrimps that are suitable. Choose an area for the tank that does not receive direct sunlight or draughts. Ideally pick a spot with a level floor and that is out of the way of the main traffic in the house. Most aerosols such as air fresheners are poisonous to aquatic life so be sure to bear that in mind.

Check list

Based on a tropical or coldwater set up here is a list of things you’ll need.

  1. Aquarium
  2. Lights
  3. Filter
  4. Heater (for tropical tanks)
  5. Air pump (if you want bubbles)
  6. Substrate (gravel or sand)
  7. Decor
  8. Water conditioner
  9. Filter starter bacteria
  10. Water test kits

Wash everything

It is always a good idea to rinse the inside of a new aquarium as well as ornaments. This is to remove any residues from the manufacturing process.

Your gravel or sand will normally require washing before it is added to the aquarium. The exception being specialist substrates for planted aquaria as this contains certain nutrients to help plant growth. The best way to wash your gravel is to add small amounts (I use around 2kg) at a time to a clean bucket. Stir the substrate by hand as you fill the bucket with tap water. Once the bucket is around 2/3 full, turn the tap off and allow the substrate to settle for a few seconds. Carefully pour off the water and repeat as many times as necessary. You should keep doing this until the water is clear. I know how tempting it is to rush this stage but keep going until the water is clean. Add the gravel or sand to the bottom of the tank and smooth it with your hand.

Half fill the tank

Place a saucer on the gravel and gently pour water onto it from a bucket or jug. This is to avoid disturbing the gravel too much and stirring it all up. Use water only from the cold tap as home hot water pipes use a different flux and can be toxic to fish. you can add a little boiled water to the bucket to take the chill off.

Add filter, heater and decor

Once the tank is half full it is time to position your filter. Be sure to read all instructions carefully and remove any inner packaging. This tank from Aqua One has a trickle filter built into the top that is fixed in place. If your tank has a separate internal power filter, the best place to position it is one of the back corners of the tank near the surface so that the flow creates gentle ripples. Most modern internal filters have a movable flow nozzle so that you can choose the direction of water to flow. It is best to position this towards the corner of the tank diagonally opposite the filter. This will ensure the most efficient circulation of water and avoid “dead spots” where there is no flow. If you are using an external filter it is best to position the inlet and outlet pipes at opposite ends of the tank.

The heater should be fitted at the back of the tank. It is best to position the heater diagonally and fully underwater. This allows the heat to rise and circulate more effectively. Ideally the filter outlet will gently pass water over the heater. This is so that the tank has no warm or cool spots and all of the water is the same temperature.

If you have an air pump now is the time to position the air stone and pipe where you would like them to go.

Now is a good time to add decoration. Think about the type of habitat you are trying to create – some fish species require specific decor such as caves or at least hiding places to feel secure. Make sure that any rocks or heavy ornaments are stable so that they can’t fall.

  • Do not plug the filter or heater in yet, this is the last thing to do.

Fill the tank

Now you may add the remaining water to the tank. Most tanks have a marker on the inside to show the maximum and minimum water levels. Add the dechlorinator (also known as tap water conditioner) using the manufacturers instructions for your volume of aquarium.

Once the tank is full you may plug in the filter and heater. Even though they are built to rigorous safety standards it is a good idea to keep your hands out of the tank whenever they are switched on. They should also be switched off before performing any maintenance.

When plugging in the filter and heater, always leave a “drip loop”. This means that the wires should droop down lower than the plug socket so that if any water gets onto the wire, it drips off. This way water cannot get into the plug and create a hazard.

Now for the hardest part…

Now is the step that fish keepers dread!


Your new aquarium is a life support system. If you have a tropical tank, it takes a little time for the heater to bring water to the correct temperature. The water isn’t yet chemically stable and this takes a while. You should, at this time, add live filter bacteria so that the filter begins to mature and will be ready for adding livestock.

Contrary to popular belief, there is no benefit to leaving the tank for a month without adding fish. Most tanks will be ready to add the first few fish after three days to one week.

You should begin testing the pH of the water as well as Ammonia and Nitrite. For most commonly kept fish a pH of 7-7.5 is ideal but this does vary from species to species so be sure to check. The Ammonia and Nitrite must be 0 ppm (parts per million).

The fun begins!

Once your water is at the correct temperature and the conditions are testing correctly you can think about adding some fish!

Patience is always key in this hobby so rather than fill your tank with fish straight away, build your stock gradually. Choose the types of fish you would like to keep together and check compatibility. Add a few hardy fish to the tank and build your stocking levels weekly.

It is best to test your water daily after the first fish have been added. This is because organic waste is now being produced and conditions can change quickly. Feed a suitable food once a day and only as much as the fish can consume in a minute or two. Once your tank is mature and stable, you can test your water weekly.

99% of problems can be avoided by simply taking your time and not overfeeding the fish. Fish are cold blooded so they don’t need as much food as you think.

And… Relax

As fish keepers, we know how much joy this hobby can bring to everybody. Fish like stability and consistency and this means that there is very little to do now other than sit back and enjoy your aquarium.

If you have any other questions or need any help or support, we’re here to help. Feel free to e-mail us at

Download this guide as a PDF here How to set up a fish tank for the first time

0 replies

Leave a Reply

Want to join the discussion?
Feel free to contribute!

Leave a Reply