How to Protect Your Aquarium During Hot Weather: 7 Essential Summer Tips

As temperatures rise across the UK, it’s not just people who feel the effects of the warmer weather, your aquarium does too.

Even a few degrees increase in water temperature can affect oxygen levels, water quality and the overall health of your fish. Whether you keep a freshwater aquarium, marine system or planted aquascape, taking a few simple precautions can help keep everything stable throughout the summer.

Here are our top tips for keeping your aquarium healthy during warmer weather.

Water temperature can rise surprisingly quickly during a heatwave.

Most tropical freshwater aquariums perform best between 24–26°C, while marine systems often require even greater stability.

Using a reliable aquarium thermometer allows you to spot changes early before they become a problem.

Direct sunlight can rapidly increase water temperature and encourage algae growth.

If possible, position your aquarium away from windows or use blinds during the hottest parts of the day to help keep temperatures stable.

Summer places additional demand on your aquarium equipment.

Check that:

• Filters are flowing correctly
• Pumps are operating efficiently
• Heaters aren’t malfunctioning
• Cooling fans or chillers (if fitted) are working properly

Well-maintained equipment helps keep water conditions stable.

Fish may become less active during particularly warm periods.

Avoid overfeeding, as uneaten food can quickly affect water quality when temperatures are higher.

Feed only what your fish will consume within a few minutes.

Higher temperatures often lead to increased evaporation.

Regularly topping up evaporated water helps maintain stable water levels and ensures equipment continues operating correctly.

For marine aquariums, topping up with the correct water type is particularly important to maintain salinity.

Your fish will often show signs if they’re becoming stressed.

Keep an eye out for:

• Gasping near the surface
• Reduced appetite
• Unusual swimming behaviour
• Lethargy
• Hiding more than usual

If you notice sudden behavioural changes, it’s worth investigating as soon as possible.

Sometimes, peace of mind is the best solution.

A professional maintenance visit allows your aquarium to be thoroughly checked, including equipment performance, water quality, filtration and overall livestock health.

Routine maintenance can identify small issues before they become expensive problems.

Whether you need a one-off summer health check, regular maintenance or a complete system service, our experienced technicians support aquarium owners across the UK.

Our services include:

• Aquarium Maintenance
• Deep Cleans
• Equipment Servicing
• Emergency Call-Outs
• Aquarium Installations
• Pond Maintenance
• Holiday Cover

If you’d like to prepare your aquarium for the warmer months, we’d be delighted to help. Email us on support@pureaquatics.co.uk or call 01275 868777 for more information.