Sunday, August 12, 2012

Mosquitoes and West Nile Virus

In our local paper this week there was an article about West Nile Virus and mosquitoes.  "A sample of mosquitoes collected last week tested positive for the virus, bringing the number of positive batches for the Halton Region this year to nine."    Two local people, so far, have tested positive for WNV.

It is high risk time for WNV illnesses.  Mosquitoes can transmit WNV to humans after becoming infected by feeding on the blood of birds carrying the virus.

Our region has promoted water conservation and the use of rain barrels for several years now.   The challenge with collecting rain water, is to keep those pesky mosquitoes from breeding in the rain barrels.   You can buy insecticide/larvicide to kill any mosquitoes from breeding in the free standing water in the barrels, however, I use the rain barrel water on my vegetable garden and don't want the chemicals on/in my food.    I have screens on my barrels, but those mosquitoes still make their way into the barrels.  It hasn't been a major issue with "standing" water this summer with the lack of rain, however the last week we've had our share of rain and looks like rain is in the forecast for the next week.    My rain barrels are full again.

So, the next best thing .... goldfish !   I bought a bag of fish from a local pet food store for 25 cents each.   The sales person at the store asked me if I was using them to feed other fish.  I said no - wanted to put them in the rain barrels to eat all the mosquito larvae.  Her response - wow - lucky fish !    I hope it works.


  1. I know it will work, because this is what others are doing here in the mountains. Our local government is spraying the river for the West Nile Virus, since the river doesn't seem to be moving at the rate it has before.

    Thank you for sharing... my rain barrels are full also - but I keep ours covered completely.


  2. Never thought to do this. We keep several layers of cheesecloth over our rain barrel. But then mosquitoes have never really been much of a problem around here as we have many bats.

  3. Good thinking. One day, we might like to have a garden pond, and I had heard that keeping fish will prevent mosquitos. I suppose it would work the same way in a rail barrel. Does your home have harsh winters? Would you need to bring the fish inside when it gets cold?
    As a kid, I had a pet turtle. Turns out turtles are not very good pets, so we found him a new home, but we kept the feeder goldfish. One of those suckers lived 14 years. Not bad for a fish I paid 5 cents for.

  4. The fish waste is probably beneficial as well.

  5. Summer 2013 update: It works !!! Rain barrels are free of mosquito larvae. We've had a wet spring this year and the barrels are always full. The goldfish were kept in a fish tank indoors over the winter and were back outside this spring. Will bring them back indoors in the fall.

  6. We use goldfish in our horses water trough and it works very well until the fish get big enough for the cats or hawks to catch. We leave the fish in the trough all year. Sometimes we get a 2 inch layer of ice over the top, but the fish seem to do just fine. Of course, we live in Arizona, so our winters are fairly mild. We do get in the freezing temps, but the fish seem to thrive in the trough. We've had them get up to about 7 inches long before the hawks get them.

  7. Do you have to feed the fish too or do they get enough from the mosquitos?
    And how do you keep them in the barrels when it rains and overflows?
    thank you so much for the inspiration!

    1. Hi Kristin. I do feed the fish as well. We put a hole in the side of the barrel a couple inches from the top and inserted some ABS pipe and covered the inside side with left window screening. When water reaches near the top of the barrel it will pour out the hole, but the mesh will prevent fish from falling out too.


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