Using Copper Pennies In Bird Baths (Natural Algae Prevention)


Do you have a bird bath in your yard? If so, you’ll know that keeping your bird bath clean is one of the most important aspects of owning a bird bath and attracting birds to your yard.

One of the biggest challenges you may face is algae growing in your bird bath. Algae naturally grows over time if the water isn’t replaced and the bath isn’t cleaned frequently enough.

There are many ways to keep bird baths clean and prevent algal growth, but one of the best methods is putting copper pennies in your bird bath to prevent algae from growing.

It is imperative to clean your bird bath as birds won’t drink from and bathe in dirty or contaminated water. 

If you’ve ever wondered why copper pennies are used to keep bird baths clean, here’s all you need to know.

Copper Pennies In Bird Baths

Placing copper pennies in your bird bath is an excellent way to stop algae from growing in your bird bath, but you need to remember that pennies aren’t all manufactured using the same materials.

Pennies made from copper work well, while others, like those made from zinc, don’t inhibit algae from growing, and they’re incredibly hazardous in bird baths.

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If you want to try keeping your bird bath clean using pennies, then you’ll have to use old copper pennies produced before 1982. Pre-1982 pennies work because they were made with 95% copper.

Never use newer pennies, as they are made with 95% zinc, which is extremely toxic. Those newer coins have a layer of copper over the zinc, but if the coating is broken and the zinc becomes exposed, it releases into the water and makes the water toxic.

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The zinc pennies only have adverse effects as they don’t prevent algae from growing, and the toxic water can make the birds sick or even lead to death.

Why Do Copper Pennies Work?

Copper is a naturally occurring algicide, so using old pennies containing copper is perfect for stopping the algae from growing.

One of the critical characteristics of copper is its biostatic properties. The biostatic properties prevent the algae from binding with the copper, and therefore the algae can’t grow in bird baths containing copper.

However, placing copper pennies in your bird bath will only partially prevent algae from growing. It will stop most of the algae from growing, resulting in a smaller amount of algal buildup.

In hot conditions (above 90 degrees Fahrenheit), the coins will be less effective as the high temperatures cause the water to be warmer and allow the algae to grow more rapidly, especially if the bird bath is in sunlight.

Are Copper Pennies Safe To Use?

Yes, you can safely place copper pennies in your bird bath to help prevent algae from growing.

However, there is a limit to how many copper pennies you should use. Using too many coins can lead to a high concentration of copper in the water and cause contamination.

Copper-contaminated water can adversely affect birds that use your bird bath, as they can be poisoned.

To prevent contamination, you should use a small number of pennies and replace the water frequently, even if the algal growth is inhibited and the water looks clean.

Knowing how many coins you should use in your bird bath is essential. The number varies depending on the size of your bird bath.

For most standard-sized bird baths, it is recommended to use between seven and ten copper pennies to affect algae growth significantly.

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If you decide to combine your bird bath with a fish pond, then there are further considerations that you need to take into account.

The first consideration is that copper is toxic to many fish species, so adding copper pennies to a fish pond can kill fish over time.

Secondly, fish rely on photosynthesizing algae and other water plants to oxygenate the water. That allows them to “breathe” and survive.

As the copper pennies are used to prevent algae growth, they also stop oxygen production in the water and can lead to the death of the fish.

To prevent the problem of deoxygenated water, you can aerate the water using a fountain to provide the fish with oxygen.

Other Cleaning Methods

Finding and adding many copper pennies to your bird bath may seem like a chore. So instead, you can place larger copper objects, such as copper piping, into your bird bath to prevent the algae from growing.

If the idea of adding copper coins and other items to your bird bath doesn’t resonate with you, then another excellent choice is to add apple cider vinegar to the water.

Apple cider vinegar kills the algae while maintaining a healthy environment and providing the birds with nutrients in the water.

Other good options are olive oil, bird bath tablets, and biodegradable balls that clean your bird bath.

You could also manually scrub the bird bath to keep it clean, but the above options require less effort.

Can You Use A Copper Bird Bath?

Yes, using a copper bird bath is a good option if you’re trying to minimize the amount of algae that grows in the bath while adding aesthetics to your yard.

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As is the case with copper pennies, you will still need to clean the bath regularly as the copper isn’t 100% effective at preventing algal growth.


So there you have it. Placing copper pennies in your bird bath is a safe, effective strategy to use when you want to prevent algae from growing in your bird bath – due to their antialgal properties.

Another benefit of using copper pennies is that they are shiny, and once they’re in the water, they can attract birds when the sun shines on them.

The most important aspect to remember is to use pre-1982 copper pennies in small numbers (seven to ten should be good), as many copper coins in your bird bath can contaminate the water.

Copper pennies only partially prevent algal growth, so it is still essential for you to replace the water and clean the bird bath to ensure a healthy environment.

Keeping your bird bath clean will ensure your feathered friends return and entertain you in your yard.

Get Our FREE Bird Feeder Cheat Sheet
Want more birds in your backyard? Get simple tips on attracting feathered friends and maximizing your bird feeding setup. Our free cheat sheet has got you covered!
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Tristan Silver

Tristan is a South African biologist, photographer, and birder. From a young age, he developed a passion for the outdoors, being taught basic biology and shown animals in their natural habitat. He picked up photography at age 11, and it led him into the world of birding and exploring. He has traveled throughout South Africa, documenting over 630 bird species. He is also interested in amphibians, reptiles, insects, and some plants. He uses photography to document his experiences and has had his photographs appear in African Birdlife magazine. Tristan holds an Advanced Scuba Diving qualification and has dived on many coral reefs. He completed his honours degree in Biological Sciences at the University of KwaZulu-Natal, South Africa. He is also a writer, expressing and sharing his emotions from his experiences through his writing, combined with photographs.

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