Keeping Your Pond Healthy in Summer

A well-kept pond can be the jewel of your garden — a relaxing oasis full of life, movement, and the gentle sound of water. But when summer arrives, rising temperatures, longer days, and increased sunlight can quickly upset the balance of your pond’s ecosystem.

Warm weather brings faster algae growth, lower oxygen levels, and more evaporation — all of which can stress your fish and plants if not managed properly. Whether you have a small backyard water feature or a large koi pond, a few smart steps can help keep your pond crystal clear and thriving all summer long.

Here’s how to care for your pond through the Australian summer heat.

Watch Water Levels and Top Up Regularly

Hot, dry days mean evaporation happens fast. Even a small drop in water level can affect your pond’s water quality and temperature balance.

• Check water levels often: Top up with fresh water when needed, especially after hot or windy days.
• Use dechlorinator: If topping up with tap water, always use a dechlorinator to neutralise chlorine and chloramines, which can harm fish and beneficial bacteria.
• Avoid temperature shock: Add water slowly to prevent sudden changes in temperature that can stress fish.

Tip: Rainwater collected in a clean barrel is a great option for topping up, provided it’s free of contaminants.

Control Algae Growth

Sunlight and warmth are a perfect recipe for algae blooms. A little algae is normal and even healthy, but too much can turn water green and reduce oxygen.

Ways to manage algae:

• Shade the pond: Floating plants such as water lilies, water lettuce, or duckweed block sunlight and naturally reduce algae growth.
• Add barley straw extract: A natural algae deterrent that’s safe for fish and plants.
• Limit excess nutrients: Don’t overfeed fish — uneaten food and waste contribute to algae.
• Install a UV clarifier: This helps clear green water by killing free-floating algae spores.

Tip: Avoid using harsh chemicals, as these can harm beneficial bacteria that keep your pond balanced.

Keep Oxygen Levels High

As water warms up, oxygen levels drop — but fish and bacteria actually need more oxygen in hot weather.

• Add an air pump or bubbler: These increase surface movement and oxygen exchange.
• Run fountains and waterfalls: Continuous water movement prevents stagnation and improves oxygenation.
• Avoid overcrowding: Too many fish can quickly deplete oxygen.

If you notice fish gasping near the surface, it’s a sign oxygen is too low — increase aeration immediately.

Manage Water Temperature

Pond water can heat up rapidly in full sun, especially in shallow ponds. Extreme heat stresses fish and encourages algae.

• Provide shade: Use floating plants, nearby shrubs, or shade cloth to protect the pond during peak sun hours.
• Deeper ponds stay cooler: If you’re building or upgrading, aim for areas at least 60cm deep so fish can escape the heat.
• Avoid topping up with warm hose water: Let the hose run cool first before refilling.

Tip: Large ponds are more stable in temperature and water chemistry — if possible, increase pond size gradually over time.

Maintain Filtration & Clean Gently

Your filter works hardest in summer as it processes more waste and algae.

• Check and clean filters regularly: Rinse filter media in pond water (not tap water) to protect beneficial bacteria.
• Remove debris: Scoop out fallen leaves and decaying plant matter to prevent water quality issues.
• Trim plants: Healthy pond plants help absorb nutrients but should be trimmed back to avoid overgrowth.

Tip: A bacterial booster product can help strengthen your pond’s natural filtration during high-demand months.

Feed Fish Wisely

Fish are more active in warm weather and will often beg for extra food. It’s tempting to overfeed — but uneaten food quickly fouls the water.

• Feed small amounts: Only what they can eat in a couple of minutes.
• Use summer formulas: Warm-weather fish foods are easier to digest and create less waste.
• Stop feeding if water is very hot: When temperatures rise above 30°C, fish metabolism slows, and they may not need extra food.

Get Expert Advice

Every pond is different — from goldfish ponds to planted water gardens and koi collections. Factors like size, filtration type, and fish numbers all affect how your pond behaves in summer.

Your local Just For Pets independent store can help you choose the right:

• Water conditioners and treatments
• Filtration and aeration systems
• Natural algae controls
• Fish-safe foods and supplements

Their team of pet and aquatic experts can guide you through a customised summer care plan for your pond — helping you maintain a healthy, clear, and balanced environment all season long.

The Bottom Line

Summer can be the most beautiful time for your pond, with plants in full bloom and fish at their most active. But it’s also the season that demands the most care.

Keep the water clean, cool, and oxygen-rich, manage algae naturally, and feed your fish responsibly. With regular checks and the right support from your Just For Pets experts, your pond will stay a sparkling, thriving haven through the hottest Australian days.