Setting Up Your First Aquarium: A Step-by-Step Guide

A well-planned aquarium is one of the most relaxing things you can add to a home. Watching fish glide through planted water has a genuinely calming effect, and a modern all-in-one tank makes the hobby far easier than it used to be. The secret to success is patience: most problems for new fishkeepers come from adding fish too soon. This guide walks you through setting up your first freshwater aquarium step by step.

Step 1: Choose the right tank

It sounds counterintuitive, but a slightly larger tank is easier for beginners than a very small one. More water means temperature and water quality change more slowly, giving you a bigger margin for error. For a first community tank, around 60 litres is a great starting point: big enough to be stable, small enough to fit on a sideboard or stand.

Look for a tank with built-in filtration and lighting so everything is designed to work together. Our Lumina 60L LED Aquarium is a design-led, beginner-friendly option with integrated LED lighting and filtration. Browse the Fish & Aquatics collection for more.

Step 2: Pick the right spot

Water is heavy: a 60-litre tank weighs over 60kg once filled, plus gravel and décor. Choose a strong, level surface designed for the weight, ideally a dedicated aquarium cabinet. Keep the tank:

• Out of direct sunlight, which causes algae and temperature swings
• Away from radiators, fires and draughty doors
• Near a power socket, so cables do not trail across the room
• Somewhere you can easily reach for weekly maintenance

Step 3: Gather your equipment

• Filter: the heart of the aquarium. It removes debris and, crucially, houses the beneficial bacteria that break down fish waste.
• Heater: tropical fish need water around 24 to 26°C. Choose a heater with a built-in thermostat, sized for your tank volume.
• Lighting: LED lighting shows off fish and supports live plants. Run it for around 8 hours a day on a timer.
• Substrate: aquarium gravel or sand, rinsed well before use.
• Water conditioner: removes chlorine and chloramine from UK tap water, which are harmful to fish.
• Test kit: a liquid test kit for ammonia, nitrite, nitrate and pH is essential.
• Thermometer, net, gravel vacuum and a bucket kept just for the aquarium.

Step 4: Set up and fill

1. Rinse the gravel or sand in a bucket until the water runs clear.
2. Add substrate to the tank, sloping slightly higher at the back.
3. Place rocks, wood and décor. Make sure everything is aquarium-safe.
4. Fill slowly with dechlorinated, room-temperature water, pouring onto a plate or bag to avoid disturbing the substrate.
5. Add live plants. They help with water quality and give fish places to hide.
6. Fit the filter and heater, then switch on. Wait 30 minutes before turning on the heater so its glass can adjust to the water temperature.

Step 5: Cycle the tank (the most important step)

A new aquarium has none of the beneficial bacteria needed to process fish waste. Fish produce ammonia, which is toxic. Over time, bacteria in the filter convert ammonia into nitrite (also toxic) and then into nitrate, which is far less harmful and removed by water changes. This process is called the nitrogen cycle, and building it up is called "cycling" the tank.

A fishless cycle usually takes four to six weeks. Add a source of ammonia (a dedicated bottled product or a pinch of fish food) and test the water every few days. You will see ammonia rise, then nitrite rise as ammonia falls, and finally both drop to zero while nitrate appears. When ammonia and nitrite read zero 24 hours after a dose of ammonia, the tank is cycled. Bottled bacteria starters can help speed things up.

It is tempting to rush this stage, but it is the difference between thriving fish and losing them in the first fortnight, a problem often called "new tank syndrome".

Step 6: Choose your first fish

Start with a few hardy, peaceful species, and add them gradually over several weeks so the bacteria can keep up. Good beginner choices for a 60-litre tropical tank include:

• Harlequin rasboras or neon tetras (in groups of 6 or more)
• Platies or guppies
• Corydoras catfish (in groups, on soft sand)
• Cherry shrimp, for a planted tank

Ask your local aquatic shop about compatibility and stocking levels. A common guide is to stock lightly at first and build up slowly.

When you bring fish home, float the sealed bag in the tank for 15 to 20 minutes to match temperature, then gently add small amounts of tank water to the bag before netting the fish into the aquarium.

Step 7: Routine care

• Daily: feed a small amount once or twice; only what fish eat in two minutes. Check the temperature and that all fish look well.
• Weekly: change 20 to 25% of the water using a gravel vacuum, replacing it with dechlorinated water at a similar temperature.
• Monthly: rinse filter media in old tank water (never under the tap, which kills the bacteria). Trim plants and wipe algae from the glass.
• Regularly: test the water, especially in the first few months.

Common beginner mistakes

1. Adding fish before the tank is cycled
2. Overfeeding, which pollutes the water
3. Adding too many fish at once
4. Cleaning the filter under the tap
5. Changing too much water at once, or not dechlorinating

Ready to start?

Setting up your first aquarium is a rewarding project, and taking your time at the start pays off for years. Explore our aquariums and fish tanks, and if you also keep other pets, take a look at our guides in the Paw & Co Journal.