Are you considering a Zen koi pond? Balancing design features and costs within your budget is key. Maintaining your tank and keeping the koi healthy also requires a significant time commitment.
When asked about what to know before creating a koi pond in your yard, Portland-based Nifelle Design Fine Interiors Principal and koi pond owner, Jennifer Leonard joked, “you should be retired and independently wealthy.”
Turns out, there are many complexities to properly maintaining a koi pond. There are high costs, which vary based on size, location and features. Water quality is important, as are feeding schedules — and even the necessity of a separate quarantine tank to isolate sick or new fish. We chatted with Pacific Northwest locals about everything you need to know before embarking on your own pond journey.
Choose the right location
Seattle-based landscape and design firm ShellScapes owner Mark Soboil highlighted the need for shade to prevent algae growth.
“In the Pacific Northwest, you can get excessive [algae] when there’s a lot of sun, just through photosynthesis,” he says. Too much direct sunlight can also make the pond too warm. Not only that, “a lot of the fir trees here have very acidic needles” you want to keep out of your pond, Soboil says.
Plan the size and depth of the pond based on the number of koi to be housed.
Soboil recommends a depth of 3 to 4 feet to insulate the fish and protect them from predators. He noted the design process includes considering filtration and aeration systems, which are essential for maintaining water quality. You also need “a filtration system that’s going to handle the amount of koi,” he says. Incorporating features like waterfalls or fountains requires the appropriate pumps, as well.
Consider local regulations and pre-installation planning
Soboil notes that, particularly in Seattle, permits may be required for digging. Planning and preparation before installation is key, especially when it comes to choosing plants and liners.
“You need to have a bottom drain for the pond for waste removal,” Soboil says. It’s important to think about the skimmer box’s location, as well, in addition to “some of the biological, mechanical filters that retain the water quality,” he says.
Source natural materials
“You don’t want something that looks artificial, like a fish tank inside your house,” Soboil says. “You want it to be more natural looking plants,” in addition to rocks and gravel for the most beautiful effect.
Acclimatize your koi
Before releasing koi into your pond, you must acclimatize. Soboil says to allow the water to circulate before adding the fish.
“We let the water circulate for a week, then we slowly add in the koi,” he says. They typically come in transparent bags and it helps to “put the bag in the pond, and leave it for 30 minutes or so before releasing them into the water,” he says.
Add ambient lighting
Create a soft, ambient glow with underwater light fixtures. Seattle-based Northwest Outdoor Lighting’s Craig Peterson says to use these instead of harsh beams that disrupt the water’s natural tranquillity. “Strategically placed uplighting can sculpt the surrounding rocks, plants and waterfalls, adding dimension, texture and a dynamic interplay of light and shadow that brings the pond to life after dark,” he says.
To further support the pond’s ecosystem, co-owner Mary Peterson recommends integrating a separate lighting zone, off switch or timer to turn off pond lighting at a designated time.
“This allows the natural nocturnal environment to take over, reducing light pollution and protecting wildlife without disrupting the lighting that might be in place for security purposes on the rest of the property,” she says.
Join local koi groups
Leonard says these groups are helpful for additional support and learning how to care for your koi. She recommends Northwest Koi and Goldfish Club (NWKGC). These groups include monthly meetings, newsletters and online forums for sharing information and advice.
Her group meets once monthly. “It rotates locations each time, which is fun because you meet at different homes, and it’s so vastly different to see what people do for their quarantine tanks and ponds,” she says.
The University of Washington also offers an extensive guide for getting started on its website: (bit.ly/3F9MtmU).
Buy from reputable sources
One of the aforementioned koi groups could be a good place for recommendations for reputable dealers from whom to purchase koi to avoid health issues like KHV (koi herpes virus).
Regular maintenance
Be prepared to maintain the pond weekly in the warmer months. Leonard notes that the time commitment varies seasonally, with winter requiring less time but still involving tasks like cleaning filters and debris.
“If nothing goes wrong, it might only take 30 minutes weekly in the winter. In the summer, it’s more,” Leonard says. Feeding habits vary, with some people not feeding their fish at all during winter (when their metabolism slows) and others following a more flexible approach based on water temperature, Leonard says.
Have a quarantine tank
Having a quarantine space is vital for adding new fish and nursing sick fish, to avoid the spread of disease.
“You can control the temperature in that tank, which is nice during winter,” Leonard says.
“You can put medicine in that water, and you always have to have a minimum of two fish in your quarantine tank” to help maintain the water quality, she says. Water movement is important for the fish, and having two fish breathing and swimming around is key. They’ll die otherwise. “They’re social animals,” Leonard says, each with their own personalities. Some of her fish are skittish, others are friendly and some have unique behaviors like laying on their sides in winter.
To further increase water movement, add a bubbler that sits at the bottom of the tank.
Maintain good water quality and test regularly
This involves regular testing for pH, ammonia, nitrate and nitrite levels. Leonard recommends using a pond master test kit from API to perform these tests, which are crucial to the health of your koi. She also suggests using a product like Ammo Lock to bind ammonia and prevent harm to the fish.
While the commitment of time and resources may be substantial, the reward is a living, dynamic water feature that brings beauty, tranquillity and the fascinating company of these remarkable fish to your outdoor space.
