Koi are one of the most beautiful and rewarding fish you can keep. They’re colourful, full of personality, and can live for decades with the right care. Don’t worry — looking after them isn’t as hard as it sounds. Here’s everything you need to know, made simple.
🌊 The Right Pond
- Size matters: Koi grow big — often 60–90cm! A proper koi pond should start at about 2,500 litres, but bigger is always better.
- Depth: At least 3 feet (90cm) so they stay safe through hot summers and cold winters.
- Filtration: Koi are messy eaters. A good filter keeps the water clean and the fish happy.
Tip: If you can see the bottom of your pond, your koi can see you too!
💧 Water Quality Made Easy
Think of clean water as fresh air for koi. Test your water regularly — it’s simple and takes minutes.
- pH: Aim for 7–8.5
- Ammonia & Nitrite: Always 0
- Nitrate: Keep low with water changes and plants
- Oxygen: Add an air pump or waterfall — koi love moving water
🍽️ Feeding Your Koi
- Summer: High-protein koi pellets = growth and colour.
- Spring/Autumn: Switch to wheatgerm food that’s easier to digest.
- Winter: When water drops below 8°C, koi rest and stop eating. That’s normal.
Golden rule: Feed little and often, only what they’ll eat in 3–5 minutes.
🐠 Koi Friends & Behaviour
Koi are social and love company. Keep them in groups, and they’ll often come up to greet you — especially at feeding time.
Good pond mates: goldfish, orfe, tench.
Not so good: tiny fish that might get out-competed for food.
🛡️ Staying Healthy
- Watch daily: are they swimming normally, fins open, colours bright?
- Quarantine any new fish before adding to your pond.
- Net your pond if herons are about — koi are curious, but herons are hungry!
❄️ Winter Care
- Koi survive winter outdoors if your pond is deep enough.
- Keep a small hole in the ice with an air pump or pond heater — this lets gases escape.
- No feeding under 6–8°C — they’re in hibernation mode.
🎉 Why People Love Koi
Koi aren’t “just fish.” They recognise their keepers, can be hand-fed, and every pattern is unique. Some people treat them like living jewels… others just love the splashes and colour in their garden.
📍 Need more advice?
Come and see us at Wakeykoi & Aquatics, Himley (Sandiacre Garden Centre). We’ll help you pick the perfect koi and show you exactly how to keep them thriving.