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What Kind of Water Does a Betta Fish Need? Water Quality Guide

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Many people think that betta fish are extremely hearty fish that don’t require any kind of special water conditions. However, from personal experience, I know this isn’t entirely true.

Betta fish require water between 78 and 82 degrees Fahrenheit, with a pH level between 6.5 and 7.5, and a water hardness level between 5 and 15. Betta fish also require zero ammonia in the water, minimal nitrite levels, and very clean water overall. Betta fish most certainly require a good filter.

Keep reading to find out everything you need to know about the exact kind of water that betta fish need to survive. 

Betta Fish Water Quality Requirements

Right now, I want to take a look at all the most important factors that you need to consider when providing your betta fish with the best water quality possible. These factors include ones such as temperature, pH level, water hardness, ammonia and nitrites, physical waste, tank space, and more.

Blue betta fish Aquarian swims in aquarium water


First, betta fish require the water temperature to be at a specific level, between 78 degrees and 82 degrees Fahrenheit. This translates to roughly 25 degrees Celsius to 28 degrees Celsius.

In terms of water conditions, temperature is perhaps one of the most important of all. If the water is either too hot or too cold for a betta  fish, it can result in a wide variety of health conditions.

This is not limited to either heat or cold shock, issues with metabolism, appetite, and digestion, immunity issues, general stress, and even death. Therefore, you always need to have a good aquarium thermometer so you can constantly monitor the temperature of the water in an accurate manner.

This way, if necessary, you can make adjustments to the temperature, either raising it or decreasing it, to suit your betta  fish. Chances are that you will need a decent aquarium heater to maintain the proper water temperature for your Siamese fighting fish.

pH level

Another one of the most important factors to consider when providing your betta fish with proper water conditions is the pH level. The pH level is also known as the acidity of the water. For a betta fish, the pH level should be between 6.5 and 7.5.

However, betta fish prefer the water to be on the slightly acidic side of things, so somewhere between 6.5 and 7.0 is ideal. The pH level is also very important for the overall health of your betta fish. Just like with temperature, if the pH level is off, it can cause some very serious health issues.

 If the pH level is not within the ideal range for a prolonged period of time, it may eventually cause the death of your fish. Therefore, you must have a pH or water acidity testing kit. This will allow you to properly monitor the pH levels in your tank constantly.

You can then take the appropriate actions to adjust the pH level as needed, either with natural means or through PH adjusting chemicals. On a side note, the pH level in your aquarium is too high, adding some authentic driftwood that releases tannins into the water can help. Those tannins will help lower the pH level.

Water Hardness

The next parameter to keep in mind when providing your betta fish with the highest possible water quality is water hardness. Water hardness refers to the amount of dissolved minerals in the water, such as magnesium and calcium.

Betta  fish prefer the water to be relatively soft or moderately hard at the most, although they do not like high levels of dissolved minerals in the water. They prefer a water hardness level of between 5 and 15 dGH. 

Once again, there are a variety of testing kits that you can use to accurately monitor the water hardness levels in your aquarium, as well as various products that can help alter the levels as necessary.

A pro tip here, if you need increased levels of water hardness, is to use a special kind of substrate that will release small amounts of minerals into the fish tank. There are also some specialized aquarium water products that are designed to increase water hardness.

Ammonia and Nitrites

One of the worst things to have in any aquarium, whether for betta  fish or otherwise, is ammonia. In fact, both ammonia and nitrites are very toxic to fish, and the levels of both need to be kept at absolute zero. We then have nitrates, which are created when nitrifying bacteria break down ammonia into nitrites, and then nitrites into nitrates.

Although nitrates are not as bad for fish as nitrates, the level should still be kept very low, below 20 parts per million. All three of these substances, when present in the water in excess, or in the case of ammonia present at all, can very quickly kill your fish. For instance, ammonia will burn your fish from the inside out.

Unfortunately, there is no avoiding having a constant supply of these toxic substances in your fish tank, because they get released when organic matter breaks down, such as plants and uneaten food. Fish waste also releases a lot of ammonia into the water.

You need to have a colony of beneficial bacteria in your fish tank to get rid of the ammonia, nitrites, and nitrates.

These are bacteria that have the ability to break down these toxic substances into inert substances that won’t harm your fish. This is generally done through biological filtration, which means that you need to have a good aquarium filter that engages in high quality biological filtration. Click here to learn more about removing nitrites from aquarium water.

Physical Waste

Although not as important as some of the other substances we’ve talked about today, it is important to remove physical waste from the fish tank. Once again, physical waste, such as fish waste, uneaten fish food, and decaying plant matter, all start to break down and release ammonia into the fish tank.

This is very poisonous to your fish and needs to be avoided at all costs. Although biological filtration is great to remove the ammonia produced by this organic matter, best is to remove the organic matter before it gets a chance to break down in the first place, and this is done through physical filtration.

This means that not only do you need a good aquarium filter with biological filtration, but one with mechanical filtration that removes physical debris from the water. Not only will this prevent ammonia and other such substances from being released into the water, but will also help keep the water from being cloudy and looking dirty.

Other Unwanted Substances

There are other unwanted substances that may get into your fish tank, particularly due to your tank water. One of the biggest culprits here is chlorine, along with chloramine. These are substances used to disinfect tap water and to make it safe for human consumption. However, this also makes tap water very unsafe for fish.

Therefore, you need to let tap water sit for at least 24 hours before putting it in the fish tank, as this will help chlorine dissipate. However, chloramine will not dissipate simply from sitting out in the open, which means that you need to use a special chemical that has the ability to remove chloramine from the water. There are a variety of special water conditioners that you can use for this exact purpose.

Moreover, tap water may also contain some pesticides, heavy metals, and herbicides, which some water conditioners may be able to neutralize. However, even better is if you have a high-quality aquarium filtration unit that also engages in chemical filtration.

This generally consists of activated carbon, which has the ability to neutralize and remove all of those substances from the fish tank. Of course, in one way or another, whether we’re talking about chlorine, herbicides, pesticides, heavy metals, and anything else, they’re all toxic to your betta  fish.

Tank Space

The final consideration here is simply the amount of tank space you provide your betta  fish. As a rule of thumb, a fish should have around 2 gallons of water for every inch of length. Therefore, if you have a 2 inch long betta  fish, a tank of roughly four or five gallons should be more than enough.


I hope that all of my tips about water quality for betta fish have been helpful, because if you follow all of them, you should be able to keep your betta  fish perfectly healthy.

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