Are you trying to set up your aquarium? If you are, filling it with water is one of the first things to do. But the question is, what type of water is best for your fish? Tap water is one of the most accessible and affordable options you can find, but how long can your fish survive in it?
If your tap water is not treated properly, then your fish can only survive in it for a few days. Tap water has chlorine content and other present chemicals that can harm your fish. I recommend letting the water sit for a few days to dilute the chlorine before adding your fish to the tank.
For the rest of this article, I aim to shed light on the effects of tap water on your fish. In addition, I will explain possible issues that can endanger your fish as well as impart helpful tips to avoid them.
Is Tap Water Safe for Your Fish?
Untreated tap water is not safe for your fish because it can contain chlorine or chloramine that can destroy the healthy bacteria that fish need to survive. When fish are exposed to small amounts of these chemicals, they may become ill. If they’re exposed to these substances for a long period, they, unfortunately, may end up floating belly-side-up.
Tap water is only considered safe for your fish if the chlorine concentration is below 0.001 to 0.003 parts per million (ppm). Any amount more than that can become fatal to your aquatic species.
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Common Water-Related Issues That Can Endanger Your Fish
Fish are significantly affected by their immediate environment. When they come into contact with any contaminants, their health can deteriorate. Toxic substances penetrate through their gills, enter their bloodstream, and often cause serious health problems.
However, the intensity of their illness can vary depending on three factors:
- species
- metabolic rate
- size
Besides chlorine, other contaminants can potentially harm your fish. I’ve listed some of the most common ones below.
Ammonia
Ammonia can be present in your tap water either through direct means, including municipal water systems and animal wastes, or indirect means such as:
- in air deposition
- nitrogen fixation
- agricultural land runoffs
Interruptions like power outages or a filter exchange can also increase the concentration of ammonia in tap water.
If you introduce new fish into your tank too quickly, you may end up changing the bio-load and expose your current fish to chemicals that your new fish were exposed to — including ammonia.
Ideally, a fish tank should have 0 ppm of ammonia. Even ammonia levels as low as 2 ppm can be deadly to fish. If your aquarium water contains ammonia, to reduce the risk of ammonia poisoning it’s essential to:
- change tank water frequently
- scoop out excess organic matter
- reduce feeding frequency
- aerate the tank
Nitrite
Similar to ammonia, nitrite is a dangerous chemical and must be kept at 0 ppm. As little as 0.25 ppm can cause substantial damage to the health of your fish.
Nitrite is produced indirectly from:
- leftover fish food
- breakdown of fish waste
- decaying matter
That being said, the more fish you have in your aquarium, the higher the chances of increasing nitrate content in the water.
Some of the methods you can perform to remedy the problem include:
- changing the water regularly
- adding half an ounce of salt per gallon of tap water
- reducing feeding times
- increasing aeration
These techniques can remove any nitrate buildup in your tank and ensure that you maintain a healthy environment for your fish.
High Levels of Carbon Dioxide
Carbon dioxide is present in water as a form of dissolved gas. This is an essential component that can help aquatic plants grow and thrive. However, if carbon dioxide exists in your fish tank in excessive amounts, it can pose a serious problem for your fish.
As much as possible, the carbon dioxide levels in your tank should not be above 25 to 30 ppm. When this happens, the gas can suffocate your fish which ultimately can lead to their death.
To avoid this problem, you need to heavily aerate your tank to diffuse the concentration and provide proper lighting so the plants can absorb excess carbon dioxide.
Tips To Help Your Fish Survive in Tap Water Longer
Despite these problems, there are a few solutions that you can try to make tap water safer for fish.
Let the Water Sit
Leave your tap water for at least 24 hours at room temperature to naturally dechlorinate it. Since chlorine tends to evaporate slowly, this process may take a few days before the chlorine completely disappears.
NOTE: I recommend letting your water sit for an average of two to three days before using it in your aquarium or fish tank.
Boil Your Tap Water
If you cannot wait several days to dechlorinate your tap water, a good alternative is to boil it for 15 minutes. This will allow the chlorine to evaporate faster while also removing bacteria that can be harmful to your fish.
NOTE: Make sure that the water cools to room temperature before adding your fish to the tank.
Use Water Conditioners
If your tap water contains the harmful substances mentioned above, a good trick is to use water conditioners. These are compounds that can neutralize chloramine and dechlorinate tap water.
In some cases, certain products can also treat hard water that contains heavy metals like iron and copper which can be harmful to fish.
Best Types of Fish To Put In Tap Water
These tips can help you create a safe environment for your aquatic creatures, but the best way to ensure the safety of your fish is to introduce species that thrive in tap water. These include the following:
- Platies fish
- Guppy fish
- Flagfish
- Congo tetra fish
- Molly fish
- Pristella tetra fish
- Turquoise rainbow fish
- Golden wonder killifish
- Odessa barbs
These are just a few of the fish you can add to a tap water tank. Others thrive just as well. Make sure to research and consult with your breeder.
The Best Water for Your Aquarium
As accessible and affordable as tap water is, it’s not the best water for your fish. Instead, many believe that filtered water is better. It contains essential minerals that can benefit fish.
If this is — understandably — out of your price point, following the tips mentioned above can help you create an ideal environment for your fish with tap water.
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