Can You Put Fish in a Swimming Pool?

As the swimming season is rapidly approaching, you might be looking for ways to spruce up your swimming pool. If you’re into making your pool look more natural, you might be pondering the idea of adding fish to it to create the illusion of swimming in a lake or sea. However, this idea is probably not the best thing to do if you want to freshen up your pool.

You can’t put fish in a swimming pool. The chlorine in the water will kill the fish in a few hours because fish are very sensitive to chlorine. Humans can tolerate certain amounts of chlorine, but fish cannot handle even the smallest quantities. 

Let’s dive into the details and see why it’s not the best idea to put fish in your swimming pool. We’ll also look at some other ideas for spiffing up your pool and making it look more natural. 

Why Can’t Fish Survive in a Swimming Pool?

Fish can’t survive in swimming pools because the chemicals, mainly chlorine, used to make pools sanitary are deadly to fish. Unlike humans, fish cannot withstand even the smallest amounts of chlorine and will die within a few hours of ingesting it. 

When you think about it, this makes sense. You have to treat your pool with chlorine (or another chemical) to prevent wildlife from moving into it and turning it into a swamp. In turn, it will be inhospitable to not just plants and bacteria but also small animals. 

Chlorine will stress the skin, gills, and respiratory system of any fish you add to your pool. They can quickly start suffering from respiratory problems and chemical burns. Those chemical burns may even be internal if the fish is exposed long enough for the chemicals to get to their internal organs. 

If you react quickly, you can save a fish that has been exposed to chlorine. However, fish cannot live in water treated with chlorine. This is why owners of pet fish are usually advised not to use tap water for fish tanks and to test their water for traces of chlorine.

Is There Chlorine in Seawater?

There is chlorine in seawater. However, this chlorine is not free in a chemical sense. Seawater chlorine is bound to sodium, creating sodium chloride (NaCl). Sodium chloride is just salt, which has no harmful effects on fish. 

Since the chlorine in seawater is a part of a chemical compound and not on its own, its adverse effects are negated by the other component of the compound, sodium. This allows the fish to be exposed to the substance without any harm. 

The ocean is also a huge body of water, unlike your pool. Since your pool is a small, closed body of water, the concentration of any chemical in it is going to be much higher than in a large and open body of water. This makes it all the more dangerous to fish, especially those freshwater fish you’d keep as pets. 

Is Chlorine Harmful to Humans?

Chlorine is not harmful to humans in the quantities that are typically used in pools. These lower concentrations are typically harmless to humans and will not cause any problems. For fish, any amount of chlorine is harmful.

The dose makes the poison, in this case. Chlorine is actually toxic to humans when ingested in large amounts. However, the amount of the chemical that is present in our pool and tap water is small enough to be harmless while just big enough to kill parasites and bacteria and keep us safe.

As the CDC says, amounts of chlorine up to four parts per million, or four mg per liter, are perfectly safe for humans. Any amount above that could be dangerous and cause respiratory and skin problems. Extremely high amounts could even be deadly. 

Do You Have To Treat Your Pool With Chemicals?

You might think that you can simply choose not to treat your pool with any chemicals and thus make it safe for fish. This would be a dangerous idea because an untreated pool poses a great health hazard.

You have to treat your pool with chemicals. Chlorine is the most common and the most effective chemical for this. Treating your swimming pool makes sure that there are no harmful bacteria, parasites, or algae in it. This keeps the water clean and safe for swimming.

Some alternative options for sanitizing your swimming pool exist, like using UV rays or ozone. However, they all need a residual level of chlorine to be truly effective, which would make your pool unsafe for fish. 

Apart from that, you need to feed fish, and they also produce excrement. Your pool water would soon become a pond contaminated with bits of leftover food and feces. These fish leftovers would promote rapid bacterial growth and make your water wholly unsafe for swimming. 

Things You Can Do Instead of Adding Fish to Your Pool

Since adding live fish to your pool is not a possibility, you’ll have to resort to some other options if your wish is to swim with fish. 

Swim in Nature

If your goal is to make your pool look more natural, why not go and swim somewhere in nature? 

You can always go to a nearby lake, river, or ocean and jump in. You’ll experience real nature without causing any harm to other living beings. Plus, you’d be getting an authentic experience that you can’t get in your pool.

Install an Aquarium Near Your Pool

Alternatively, you can place a fish pond or large aquarium next to your pool and arrange it so that it looks as if it were part of the pool. If you have small kids, putting pool-safe mechanical fish in is also a good option. This will be a fun and safe addition to your pool.  

Final Thoughts

Putting live fish in your pool is not an option since fish cannot tolerate chlorine and can die if exposed to it. Since all other options for pool sanitization need a residual level of chlorine to work, it is not possible to have a pool with fish that’s also clean and safe for swimming. 


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