The first time I told my neighbor I was putting goldfish in my rain barrels, she looked at me like I’d lost it.
“Goldfish? In what?”
Yep. In my rain barrels.
It started over ten years ago. Back when we still had stacks of gardening magazines piled on the porch. I read about rainwater harvesting and thought, Sounds easy enough. So I got my hands on two old whiskey barrels and stuck them under the gutters. Felt like I was being responsible. Sustainable. Clever, even.
But then came the mosquitoes. Ugh. I didn’t expect a full-blown mosquito rave setting up shop in my carefully collected rainwater. But I should’ve known. Mosquitos love water. Water attracts those annoying insects.
I looked into solutions. There were pricey screens, fancy filters, even tablets to kill larvae. But all I wanted was something simple. Cheap. Preferably alive.
Enter: the humble feeder goldfish. Yeah, my husband was skeptical too, but listen.
Why Mosquitoes Love Rain Barrels
Before I get into the fishy part, let’s talk mosquitoes.
Rain barrels are perfect little incubators for them. Stagnant water? Check. Shade? Check. No predators? Double check. A single female mosquito can lay hundreds of eggs in just a bit of standing water. That peaceful barrel? It becomes a baby bug nursery in no time. Disgusting, annoying, let’s say – not pleasant at all!!
And believe me, nothing ruins a summer evening in the garden faster than getting eaten alive while watering your tomatoes.
The Low-Tech, No-Chemical Solution
So here’s what I do every spring.
I head to the local pet store and buy a few feeder goldfish. Usually the cheap ones. The kind that cost about the same as a candy bar. They’re not fancy. Just tiny orange swimmers with a strong appetite for mosquito larvae.
I gently place them into my rain barrels. That’s it. No filters, no pumps, no food. These fish live rent-free and do the work for me.
They munch on mosquito larvae. They eat up algae. Sometimes they go after whatever else drifts into the water. I don’t clean the barrels. I don’t treat the water. Nature takes care of it. It’s like a tiny pond ecosystem, right outside my kitchen window.
Do the Fish Survive?
Surprisingly, yes. Most of the time.
At the end of the season—usually before the first frost—I scoop them out. I bring them indoors for the winter. A basic tank with tap water (left out for a day or two to dechlorinate) works just fine. If I’m feeling generous, I toss in a few pond pebbles and one of those bubbling air stones. They seem to enjoy it.
Then, once spring comes and the water warms up again, back they go. It’s like a weird little reunion. And honestly? I’ve grown attached to the little guys.
One time I accidentally dropped a slice of toast in the barrel while feeding the fish. They seemed confused, but I swear one of them took a nibble.
I once had a goldfish live four years doing this seasonal routine. His name was Kevin.
Kevin was a legend.
Why This Works
Goldfish in rain barrels may sound odd. But it works for a bunch of reasons:
- Natural mosquito control
No chemicals. No mosquito dunks. Just hungry fish doing their thing. - Free water movement
The fish create little ripples. That helps stop mosquitoes from laying eggs in the first place. - Built-in fertilizer
This is the part I didn’t expect. Fish waste makes rainwater even better for your plants. It’s packed with nitrogen and other goodies. When I use that water on my veggies? They practically high-five me. - No maintenance
Seriously. I don’t scrub anything. I barely check on them. If the water gets low, I let the next rainstorm top it off.
Simple, right?
A Few Tips
- Don’t use chlorinated water to fill your barrels. Rainwater is best. If you do use tap water, let it sit out for 24 hours first.
- Keep barrels shaded if possible. Too much sun can make the water too hot.
- Don’t add too many fish. One to three per barrel is enough.
- Make sure there’s no way for them to jump out. Yes, goldfish can jump. Who knew?
- Cover the top loosely if you’re worried about birds or predators. I’ve had a curious raccoon visit once. Kevin survived. The lid didn’t.
- Don’t panic if the water turns green. That’s algae, and the goldfish love it. They’ll eat it like salad.
And if you suddenly find yourself naming your fish and talking to them while sipping coffee on the porch—well, welcome to the club.
Eco-Friendly Bonus
Here’s a bonus I nearly forgot: fish poop is gold. Hear me out before you judge me. Garden gold. That nutrient-rich water goes straight into my beds. I swear my zucchini doubled in size once I started watering with “fish tea.”
It’s the circle of life, backyard edition.
And if you’re into zero-waste, this method checks all the boxes. No plastic barrels and chemical treatments. No extra waste. Just rain, fish, and patience.
The Weirdest Ideas Often Work Best
I realize this might not be the gardening advice you’d often at gardening centers. But honestly? Also, strange though it may seem, sometimes the weird ideas are the ones that work the best.
I realize that goldfish in rain barrels sounds a tad nutty (or more than “a tad”). Yet this is no mere silly trick. It’s low-cost, it works and it can even be a little bit fun to do. And it gives a life to those little feeder fish in the tank at the corner pet shop.
I mean, I never thought I’d give a hoot about a goldfish named Pancake, but here I am. At one point I was actually Googling “can goldfish get lonely” at midnight while I was eating cereal.
And what do I get out of it? Softer water, fewer bugs, and healthier plants. I’ll take that deal any day.
If you’re fed up with mosquitoes and not thrilled about pouring poison on your yard (cuz who is?), give this a try. It’s straightforward, yet effective, yet the right amount of weird.
So have at it — now you can be that neighbor with fish in your rain barrel. You might start a trend.
