Did You Know? Goldfish and Rain Barrels

goldfish and rain barrels
Photo courtesy of www.prwd.org

Many people have rain barrels. Where I live, you can spend $35 and a couple hours and build your own. Then you have the ability to capture rain water from your roof and use it to water your garden. That’s a pretty good tradeoff in my opinion. Lots of people are concerned about mosquitoes breeding in their rain barrels. There is a mosquito netting that you can put on top that also serves the purpose of keeping debris like leaves out. But there is still a concern that the mosquitoes could make their way in to populate. So what can you do about it?

Use goldfish. While goldfish and rain barrels may seem like an unlikely pairing, they can actually work quite well together. The goldfish will eat any skeeter larvae but you may still need to give them some supplemental food. Unless your rain barrel is open to the air without netting, the volume of larvae won’t be enough to sustain your goldfish.

goldfish and rain barrels
Photo courtesy of www.desktopgoldfish.com

If you decide to use the combination of goldfish and rain barrels, make sure that your spigot is high enough from the bottom so that when the barrel is “empty”, there is enough water left to support your fish. Buy the small feeder fish from the pet store to use in your rain barrel. And make plans for them when the season is over. I guess that you could technically bring them indoors in an aquarium when the temperatures drop but I think they would be better off in a water garden if you have the capability. If not, ask a friend or neighbor if they’d like some free fish…chances are they’ll say yes.

Have you used goldfish in your rain barrels to successfully keep your mosquito population down? If so, leave me a comment below or shoot me an e-mail. If you enjoy being part of the Mid-Atlantic Gardening community, join our e-mail list (upper right hand corner of this page), become a fan on Facebook and follow me on Twitter. Happy gardening!


July 23, 2012Permalink 23 Comments

23 thoughts on “Did You Know? Goldfish and Rain Barrels

  1. I rescued and repaired a 500 gallon livestock tank. By accident I added 12 goldfish and 2 koi 3 years ago, They love the mosquito larvae, at the end of the season, once it starts to get cold, they go into a state of dormancy. Goldfish are quite resilient, they can stand the cold.

    • Great info Gregory! In such a large tank I’m sure they do quite well. If someone was using a smaller 50 gallon rain barrel, I wonder if they would survive as well? If anyone has any thought, please share!

      • We just purchased Garden Anywhere Boxes and the owner says he keeps goldfish all year, even through freezing temps, and his rain barrel looked a bit smaller than 50gal. He said if it freezes, they thaw out when the water thaws out. He has had his for years, in central OK.

  2. I would like to know more about this. We have a small yard with a few small fountains. The birds love the water, but the pumps are only on when we are outside and the result is mosquito breeding ground. I’d love to have a few fish, but given the small size of the bases I’m worried about overheating. The biggest one is about 18″ diameter. It has only minimal shade but I would add shade if that would be adequate. It does have hiding spots. Also would birds go after the fish? And will the fish help with algae build up? Or do we just need to stick with regular cleanings of the fountains?

    • Hi Jamie! Given the fact that your fountains are small (and shallow I assume) you may be better off with mosquito dunks. They are made from a natural organic material known as Bti. It doesn’t have any negative side effects on animals and the dunks last for 30 days. You’ll still need to do your regular cleanings as the dunks won’t help with algae. I hope this helps!

  3. I have both a pond and rain barrels. The pond (which is relatively small at 160 gallons) has fish — comets and some volunteer mosquito fish that we think came in as eggs on some plants.

    I think fish would do okay in a rainbarrel, but I have to say that even if they survived you might not want them there. Goldfish are notoriously dirty fish — lots of poop, etc. I think the smell would be a factor after a while. Other fish might not do well, then you’d have a different smell — that of dead fish.

    Mosquito dunks, as noted by others, would be a good solution. That’s what we use in our rainbarrels, and it helps. Even though the screens keep out big critters, I still was finding mosquito larvae in the water last year, which is why I started using the dunks myself.

    FWIW: the area that is the most “mosquito free” in our yard is the area near the pond. I would love to learn more about the exact science of this… but I am sure those fish eat a lot. I don’t feed them anything now that my pond is established. They don’t need it! They get enough to eat from the pond and the insects, etc. Dragonflies are numerous near our pond — this summer we’ve had a lot of different species I never saw before the pond was installed. I am sure the mosquitoes are being eaten by the dragonflies, as well as the fish.

    • Hi Alison! Mosquito dunks are certainly another option for keeping the mosquitoes at bay. But for the more eclectic or those who don’t wish to purchase dunks, the goldfish provide a viable option as well. The water should be moving through the rain barrel on a pretty regular basis if you are using it for your gardens. And the fish poo will provide fertilizer for the garden too. As to the area nearest your pond being the most mosquito free, I think it’s a testament to the volume of larvae that your fish are eating. Thanks for stopping by…come back soon!

  4. Three summers ago my son dumped a feeder goldfish he won at the county fair into my little 40 gallon pond I installed to capture stormwater from 2 downspouts. The fish not only ate mosquito larvae, but also anything else that moved, especially gray tree frog tadpoles. The water did get mucked up a bit, much less clear. I only fed this fish about 5 times during the three years. I was secretly hoping it would starve and die so I could get the ecosystem back in check. It grew steadily and survived the winters, even when the pond froze halfway to the bottom. I was quite impressed with its resiliance. Topping out at about 8 inches long this spring, the goldfish started hanging out on the pond surface, which led to his demise when passing great blue heron ate him for lunch. The pond water has cleared and I have loads do tadpoles again (3 frog &1 toad species), dragonflies, water boatmen and other insects. I have also used mosquito fish to control mosquito larvae, but they don’t tend to survive the winter in shallow ponds.

    • Great info Cindy…thanks for sharing your experience. I can’t tell if you’re happy that your son’s goldfish is gone or if you secretly miss him for mosquito control. 🙂 Thanks for stopping by!

    • I glad to hear that I’m not the only one with a bird feeder! Same thing here, I’ve used 50 gallon barrels to collect rain water. And goldfish to control misqutoes . And a small pond/ bird feeder. Again with goldfish. Lastly in winter I dump everything into a fire pond. This also supplies water for my bees.

  5. I’m from central Canada (Winnipeg) and we have an open rain barrel below our main downspout. We usually buy a dozen feeder goldfish and through them in the barrel. We did that two years in a row. Usually more than half die and we scoop them out when that happens, but at least three or four make it through the season. When the rain barrel starts turning to ice I scoop them out and post ad for free fish on kijiji. We never feed them, but one year we had floating pond plants. That was the same year squirrels kept drowning in the bucket. However, that year none of the fish made it past a week, and it may because it was our first season with a new roof.

    • Hi Ruth,
      I am also from Winnipeg. I plan to use a 55+ gallon drum with a 100 watt submersible heater. I wil also have a water pump with no hose at the bottom of the drum, facing upward to keep the water agitated enough to not freeze over in winter (I’m hoping between the heater and the water pump, that I will have all fish and plants survive). I was also thinking of making a windbreak or some kind of cover from the wind. Sorry if this sounds like broken english with terrible punctuation…it’s tough on a phone.

  6. Hi there, I have put some goldfish into my rain barrel and they seem to be doing fine. I have been wondering about adding some aquatic plants to the bottom of the barrel to help with the ammonia levels that will increase as the fish “poo” in the water. My concern is that the plants won’t receive enough light to survive. Has anyone else tried this? Any ideas or thoughts?

    • As you use the water, you should be releasing the ammonia as fertilizer so it should be a win-win. Who else has thoughts?

  7. Hi all, thanks for the advice. I have a pond with a four foot waterfall. Pond is about 7′ long by 10′ wide and about 28″ at its deepest area. I think it should be around 800 gal or so. I have a small filter and small basket pump (about 500 gph) in the middle and a large pump (1700 gph) attached to a skimmer and larger sealed bucket type filter. They both have UV lights. I currently have two small Koi fish (about 5″ right now) as my test fish. There is plenty of water movement in the pond and the fish seem to like it. But I still have noticed a few mosquito larvae hatching every night. I am using mosquito dunk (1/2 disk as recommended) also. I think after reading this I need a couple of goldfish. My pond is big enough but I know koi and goldfish get pretty big. Plus I do not want a lotta waste to clean up. Not to forget that I still have a lot of algae on the rocks and bottom. Any suggestion on algae & mosquito eaters that will survive cold Nebraska winters. And if I do have to much fish waste, how do I get that stuff out without draining my pond or having to reroute my existing plumbing? Thanks for reading.

  8. We had a half whiskey barrel bog garden that someone convinced us to buy two goldfish for. They kept the bugs in check the first year, and so we wintered them over in the unheated garage, where the 25 or so gallons were frozen hard for about a month, but they survived. I felt so bad for them, I put a 150 gallon stock tank in the backyard this last year and gave them a variety of aquatic plants. They grew to 6 or so inches long each, and seem very happy. This winter I broke the ice daily on the top of the pond and they have survived. Spring is around the corner, and many of the plants made it too! Here in the Pacific Northwest we need semi hardy plants, and luckily goldfish and anachris seem very hardy to me. A goldfish needs a buddy, and they both need at least ten gallons each to be happy, but as I learned above, unless you have enough water it will freeze over, and they need oxygen. But great bug eaters and plant fertilizer makers! We love their personalities, they recognize our faces and come to the surface to be fed in the warm seasons.

  9. We live at the SC Coast. Got a 5 gal plastic barrel from a car wash about 16 years ago.
    Put about 8 feeder fish in there. They winter in there very well in our climate. Ice may form on top, but they stay at the bottom. I try to keep thr ice broken, but it has frozen over and they were ok anyway. They live about 4 or 5 years. They have lots of larvae to feed on and we give them a bit of food once in a while.

  10. I was wondering about the water getting too hot in the summer months for them? Temps can get up to 100 degrees. Anyone have an issue with this?

  11. Feeder goldfish work great. And no mosquito larvae. No need to feed them but occasionally I rinse a dinner plate into them. I lose about half in the first week or so but if they live past that, they are good for the season.

  12. I was thinking about starting rain barrels to water my chickens….Would that be safe for the chickens?

    I was thinking of doing the type of barrel that just catches the rain and not the runoff from the roof.

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