When we moved into our new French home, I promised myself that one corner of the garden would become something truly peaceful, a little oasis where the sound of trickling water would replace the hum nearby traffic. Fast forward to a warm August afternoon, and there we were: sun hats on, shovels in hand, and an ambitious plan to build our very own koi pond.
It started, as most of our projects do, with my husband and I saying, “How hard can it be?” (Famous last words.)
He’s the practical diver in the family - a true water enthusiast - while I’m the biologist, forever fascinated by aquatic life since my marine biology study days. So between us, we had the enthusiasm and the science covered.
The digging began in late summer. The days were hot, the soil was unforgiving and rock solid, and Loona was only too happy to “help” by running through the piles of earth. Slowly, shape took form- a gentle curve to mimic a natural pond, with ledges for marginal plants and a deeper section for the koi to glide through in winter.
Cycling the Water: The Science Behind the Wait
Once the liner, pump, and filtration system were in place, the next part was less about shovels and more about patience.
A koi pond isn’t just a big bowl of water it’s a living ecosystem. Before any fish can move in, the pond needs to be cycled, a process that allows beneficial bacteria to grow and establish a biological filter. These microscopic helpers convert harmful ammonia (from fish waste or decomposing matter) into less toxic nitrates, keeping the water healthy and stable.
That’s why, even though we started in August, it wasn’t until October that our first koi finally swam beneath the surface. Cycling takes time you can’t rush nature. We monitored the water chemistry carefully, testing for ammonia, nitrite, and nitrate levels, adjusting as needed. It felt a bit like running a miniature science lab in our own garden, and honestly, I loved every second of it.
Meet Our Doitsu Japanese Koi
When the water finally reached perfect balance, we took a little celebratory trip to a newly opened local koi shop - a dangerous place for two fish enthusiasts! We fell in love instantly with their collection of Doitsu koi, a Japanese variety known for their smooth, scaleless bodies and beautifully clean colour patterns.
Unlike traditional koi, which are fully scaled, Doitsu koi either have a neat row of mirror-like scales along their dorsal line or are completely smooth. The result is a sleek, almost porcelain look that shows off their colours from deep reds and inky blacks to shimmering whites with incredible clarity.
Ours are young, curious, and already developing personalities of their own. Watching them glide gracefully through the pond feels hypnotic, especially at sunset when the water glows like amber. We have decorated the area with some solar lights its really rather pretty at night. We have started a rockery beside it and hopefully by next summer the plants will be strong and beautiful.
A Piece of Calm in a French City
Now, a few months on, the pond has settled beautifully. Water lilies dance on the surface, the gentle hum of the pump fills the air, and Loona lies nearby watching the fish with quiet fascination (thankfully without trying to join them).
There’s something deeply grounding about tending to water checking the parameters, feeding the koi, noticing small changes each day. It’s part science, part mindfulness, and all heart.
There is still work to do like finishing the edging, adding more stone, planting the rockery and fixing the netting over the top but we have made great progress and are already loving it. For us, this pond isn’t just a new feature in the garden. It’s a reflection of who we are: two people who can’t resist anything with gills, fur, or feathers finding beauty and balance in our little corner of France.
Next up on Paws in Cher
I’ll be sharing some tips for maintaining healthy pond water and feeding koi through the colder months — plus a few ways we plan to add plants and lighting next spring to make the space even more magical.