How to Build Your Back Yard Goldfish Pond

I never considered digging a giant hole in my back yard and filling it with water until I saw the preformed pond kit at Home Depot one day. I instantly fell in love with the idea of having a pond in my yard and was glad to see it wasn't cost prohibitive.

They only had two pond shells to choose from, so I went with the bigger one which held just under a hundred gallons.

I also purchased a basic filter, a water pump, grabbed my trusty shovel, and got to diggin.' I even found a little waterfall kit to make it extra fancy and such.

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The biggest decision when planning a pond is the one you want to spend the most time thinking about: where to put it? Obviously, changing your mind and redigging a big hole in your yard isn't fun for anybody, but there are other things to consider besides aesthetics.

You're going to need some power to the pond for your pump, lights, de-icers, etc., so plan accordingly. I decided to place my pond right up against my garage so I had an outlet just a couple of feet away. Speaking of outlets, water and electricity don't mix, so make sure you install a GFCI outlet for anything related to your pond.

It's also not a good idea to place your pond directly under a tree unless you want to spend all autumn fishing leaves out of it. And finally, make sure you check with digger's hotline before you get started. Hitting a buried gas or electric line with your shovel = bad.

So you picked your spot, bought your supplies, and made sure there's nothing but dirt under your feet. Great! Start digging, donkey. I won't lie, it's a lot of work and monotonous, but I enjoyed it. It's good exercise and rewarding because you're digging for a worthwhile goal. Just take your time and don't forget a good pair of work gloves, otherwise it's blister city.

If you use a preformed shell, it's pretty easy to get the basic outline of where to dig just by placing it where you want it to go. Once you get past the sod and start getting deeper, it's a game of trial and error to get the hole just right.

You'll have to mess around with back-filling the hole to support the bottom and sides of the shell. Be sure to put a level on it. You'll want the dirt under and around the sides of the shell as tight as you can get it because once this puppy is full of water it's going to want to settle.

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I got a little fancy with a preformed waterfall shell and some tubing to create a waterfall. It's a good use for all that dirt you dig up! Where to put the rest of it is up to you.

The end result was....okay. The whole project took me two weekends and I was pretty happy with it. I let the vegetation around the pond to grow out and added a couple plants in the pond to make it look a little more natural.

So now that I've said all that, let me give you a little advice. DON'T use a preformed shell for your pond. It only took me about a year to regret that my pond was too small and that's pretty much the biggest shell they make. Plus, it was a pain to dig the hole just right if I'm honest.

After a couple of years I decided to drain the pond, yank out the shell, and dig a much bigger pond using a flexible PVC liner. Otherwise known as a big-ass sheet of rubber-like material. It's much easier to install and can be cut to size for a custom pond.

Once my old pond was drained, I pulled out the shell and flipped it over, using it as part of a small hill next to the new pond that will be part of the waterfall.

How you design the shape of your pond is up to you, as long at the liner you purchased is big enough. You'll want to vary the depth not only for aesthetic reasons, but for function as well. One end of my pond starts off shallow and gets deeper, just like at the beach. The shallow end gives my goldfish a spot to bask in the warmer water on sunny days and encourages birds to stop in for a splash and a drink. We even attracted a frog last summer.

This guy showed up one day out of the blue and moved in. His name is Froggy.

Build in a shelf along the perimeter of the pond to place potted plants and make sure you have at least one deep spot in the pond that won't freeze over in the winter. Even if you're not planning on fish, I would recommend doing this in case you ever change your mind. Goldfish can survive in the coldest of winters but not if they're frozen solid in the ice!

How deep you have to dig is based on where the frost line is in your neck of the woods. Basically you need to dig deep enough to where the soil doesn't freeze in the winter. Here in Wisconsin, I dug a "well" in my pond that's about 3 feet deep and about 2 feet around.

Once you're done digging I would recommend waiting a day or two. Study that hole and let it sink in. If you want to make any changes to the shape or size, now is the time to do it before the liner and water get put in.

Before you lay the liner, make sure you've removed any sharp rocks sticking out from the dirt. Pond liners are pretty heavy duty stuff, but better safe then sorry. Once the liner is in place, it's just a matter of breaking out the hose and filling it up, smoothing and adjusting along the way.

Once the pond is full, let it sit for a day before trimming the excess off the liner. You'll want to give everything a chance to settle. Allow an overlap of six inches or so around the rim of the pond. I used irregular pavers to hide the edge of the liner, keep it in place, and offer a more natural look.

As you can see from the photos, I used all the dirt I dug up to create a small hill next to the pond. It provided a base for the waterfall I built and added to the scene I was going for.

Here fishy fishy....

I didn't plan on putting fish in the pond until one day when my son came home carrying a plastic bag full of water with a gold fish floating in it. He'd won it at the local fair and asked if it could go in the pond.

A few years later, and we're up to almost 30 gold fish. I think we bought around 10 and the rest were born naturally in the pond with no input from us. Mother Nature finds a way to do her thing! Nothing fancy, just regular old goldfish at the store for 39 cents a piece.

Not only are goldfish beautiful and soothing to watch, but they're extremely tough and hardy. They'll survive in the coldest of winter and practically take care of themselves. Toss some flakes in the water once a day for supper and they'll be happy.

A few points about goldfish:

• Stay away from the fancy and expensive varieties until the ecosystem in your pond is balanced and mature (more on that later). I mentioned goldfish are tough, but I'd be lying if I said I didn't have a few casualties here and there when I started out. Those cheap feeder fish might be a little boring when they're young, but in a large pond they'll grow quickly into beautiful adults. You won't believe how big they grow in no time!
• Don't forget the shade and a place to hide. It gets hot in the summer! If your pond is in direct sunlight, give your guys some shade with plants. No need to get fancy. Simple potted grasses do quite well submerged full time. See that grass in the picture above? That's actually attached to a large chunk of sod I dug up from my yard and chucked into the shallow end. It's doing quite nicely. A ceramic flower pot tipped on its side provides a cozy cave. Get creative!
• If you have quiet places to hide in your pond, don't be surprised if your fish get busy and start making some babies. I found the females seemed to like my grassy area to lay eggs and it's a good place for the fry to hide out until they're grown. We started out with 10 original fish and we're up to almost 30 naturally.
• Bodies of water are a breeding ground for mosquitos, right? Not so fast, you little bloodsuckers! Skeeters may try to lay eggs in our pond but you can be sure my goldfish eat 'em up before they ever get to experience the taste of human flesh. Good fishies...
• Simple goldfish flakes do fine for feeding time with a few worms once and a while for variety. Once fall sets in and the water temp is consistently under 50 degrees, stop feeding. Fish can't process food in the cold weather and it can actually harm them. Don't worry, they'll be fine with no food until the water warms up in spring.
• Your guys will survive the winter, but you'll need to take a few precautions. Besides not feeding until the water hits over 50 degrees, you'll wan't to turn off all pumps and filtration for the winter. The fish will get very slow, sluggish, and lazy in the cold water - almost hibernating. They like things calm and quiet. It's okay if the surface freezes over completely, but you'll need at least a small hole in the surface so carbon dioxide can escape. Otherwise the fish could die. There are de-icers specifically designed for this and do a great job.

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De-icer in action. It was -2 degrees when I snapped this picture. It's not to keep the fish warm, it's so carbon dioxide can escape and oxygen can get in.

Ranger patiently waiting for spring so he can get back to some good old fashioned fish stalking.

Filtration and aeration

Unless you go crazy and your pond is the size of football field, you're going to need a way to filter the water and make sure it's got plenty of oxygen. Nature will find a way to balance everything out if the conditions are right, but it takes a while for a natural ecosystems to establish. The size of your pond is a factor - smaller ponds require more man-made intervention where larger ponds tend to take care of themselves easier.

As far as aeration goes, you can go with a simple pond fountain or create a waterfall. There are many different approaches to designing and building waterfalls, so I won't get into any specifics here. Spend some time perusing the web for instructional videos and articles to get some ideas.

I started out with simple box style filter but eventually upgraded to a UV pressure filter which made a world of difference. The pressure filter is nice because you can place it outside of the pond so it doesn't take up room or look ugly. With any kind of filter you'll need tubing and a pump based on the size of your pond.

I'm not going to lie - don't expect shimmering crystal clear water even once you get a filter going. You'll have days where the water is so cloudy you can barely see your fish. There will be times where the water is green and you have algae floating on the surface. Relax and be patient. A pond is a living thing and takes time to establish. Good bacteria needs to grow to keep bad bacteria at bay. Plants, fish, water, bugs, microorganisms - eventually they'll find a way to balance out and you'll be rewarded with clear and healthy water. Crack open a beer, relax, and resist the urge for chemical intervention.

Very crude sketch of how my pond is laid out. Water is pumped into the filter and out the waterfall, getting aerated in the process.

New deck I built last year. This photo is from early May. By fall, natural vegetation on the left side of the photo is much more prominent.

I dug a second pond seen here on the left in 2015. My plan was to join the two, but it didn't work out.

Second pond. I had a duck couple visit shortly one morning. They swam around, took a drink, and flew away.

So have I temped you to dust off that shovel in the garage? I hope so, because our pond is my favorite thing about our home. I can't tell you how relaxing it is to sit out there after work, beer in hand, watching my fish swim around and listening to the soothing sound of the waterfall. I only wish it was bigger. Oh, and by the way? This summer I'm making it bigger.

Any questions? I'm no expert, but I can answer anything based on my experience. Comment below and I'll get back to you.


Robert Brumm is the author of several books and has only fallen into his backyard pond three times. Out of those three he was pushed once. Please hand him a towel and subscribe to his blog.