How To Prepare & Test Water For A Betta Fish

In this article we’ll cover how to prepare and test water so that you can ensure the water conditions for your betta fish are always at the correct standard.

A Quick Primer On Water For Your Betta

Bettas are freshwater fish. In the wild they live in shallow, slow-moving streams, rice paddies, ponds and swamps. As you probably know, the water from a stream or pond is totally different to the water from your tap. Water from a tap has additives and treatments that make it healthy for humans but unhealthy for fish. Tap water has chemicals like chlorine in it to make it sterile. These chemicals will kill your betta if you don’t treat the tap water before introducing it to your aquarium! Water can vary from source to source in density, acidity, minerals and pH.

Different types of water that you might use for a betta

So how do we get the ‘right’ water for a betta fish? Typically there are few water sources you may encounter when learning to care for a betta. Here's what you need to know about them:

Tap Water

The water MUST be treated before you put into the aquarium. If you introduce a betta to tap water without it being treated, your fish will die. If treated correctly, this water will be fine.
Tap water is a reliable as it's constant and affordable water source.
On average tap water tends to have good enough pH levels and mineral levels for a betta. It's best to test these parameters before using it for your aquarium as if not adequate you'll have to adjust the mineral and pH levels of your tap water. This should always be done before adding your fish but chances are you won't have to make these adjustments.

Read more about treating tap water below.

Bottled Water

You may sometimes see bottled water sold as 'betta water' in pet shops or online. This to us is more of a cheap scheme than a practical water source for your betta. We recommend just using tap water.

It may say the water is 'mineral water'. It's true that there may be beneficial natural minerals in the bottled water but the resulting pH of bottled water can vary depending on the provider. It’s best to test the water with a pH test kit. Although you can add your betta to this water without conditioning it - very quickly this method will become more expensive compared to simply buying water conditioner (or other water treatments) to add to tap water.

Pet Store Water

Professional aquatic and pet stores sometimes sell pre-conditioned aquarium water. This isn’t typically used for freshwater fish (more so marine fish), as preparing aquarium water for freshwater fish is easy, it just takes patience. If you want a batch of water ready for your betta, don’t hesitate to ask in an aquatic store, especially if your betta aquarium isn’t too large. This isn’t the most affordable way of acquiring water, though.

Water that you should defiantly not use for your betta

Distilled water

AVOID distilled water: this is a bad choice for aquarium water. Pure H20 doesn’t sound like a bad idea at first, but it isn’t the healthiest option for your fish. Bettas need minerals — it’s essential to their health. Distilled water will contain no minerals. Distilled water also tends to be quite expensive, which isn’t worth it if it’s not going to be beneficial to your betta.

Testing Water pH

What is pH? pH is the level of acidity or alkalinity found in the water. An uneven balance can certainly cause your fish death. So, what’s the right number and how do we find the pH level of aquarium water?

Bettas live happiest at a pH level between 7.6 or 6.0. There are 2 ways of finding the level of pH. Do it yourself, or get someone to do it for you. A pH aquarium test kit is inexpensive and easy to use. Instructions for use will usually come with the kit, but as a summary, here’s how they work.
To note, both these tests do go out of date, the indicators get weaker over long periods of time. Make sure to check the date or the kit you acquire. A new kit should give you good accuracy for up to 3 years.

Test kits usually come in 2 forms: strip tests and tube tests.

The tube test kit will give more accurate results out of the two. Collect a sample of the aquarium water using the test tube and add the liquid indicator that comes with the kit. The water will change colour, the same way as the strip does, indicating the level of the pH via colour. The colour guide to the pH will be with the kit.

The strip test is similar, the kit will come with some paper-like strips, and you dip part of the strip in the water, shake and wait for a minute. The paper should eventually change colour. Match the colour of the strip up against the pH chart that comes with the kit. If it’s a solid green colour then the water will be fine for your betta. Again, there’ll be an indicator with the kit.

Examples of Test Kits:


Aquarium Test Kit by API (view it here on Amazon)

We've been using this kit for many years and have found it to be reliable and accurate. The instructions that come with the kit, as well how to determine your results, are simple and easy to understand. This kit tests for pH as well as a number of other parameters you'll need to know when keeping a betta.

pH Only Test Kit by API (view it here on Amazon)

This is a cheaper version of the API test kit above. It's still useful, but you don't get as full a picture as the one above because you aren't testing as many parameters.

5 in 1 Test Strips by API (view them here on Amazon)

These are useful to get a quick snapshot, but overall you don't get as much information as you do with the test kits we've recommended above.

What If Your pH Level Is Not Right?

We only need to look at part of the scale. 6.0 to 7.6.Ideally you’ll want a pH within these figures. A natural pH for a betta is 7.00, neutral - but a stable pH is much more important than an ‘ideal’ pH.What do we mean by stable?Well if you test your pH 3 times a day and it moves by say no more than 2 or 3 points from say morning to evening. 7.0 in the morning then 7.2 in the evening is harmless.For example, in the previous episode we cycled our aquarium at the start our pH was 7.0 and by the end it's dropped to about 6.8 which is an expected fluctuation due to some natural chemistry happening in the aquarium.If within 24 hours it bounces from 7.0 to 7.6 to 6.4 to 7.2 to 6.0 from acidic to alkaline to neutral - this is trouble.So if this is indeed the case or your pH is too high or too low or your aquarium is cycled - this is a major indicator that the percentage of the minerals in your water is way too high way or too low and is most likely causing the issue with your pH.Too many minerals can neutralise the somewhat needed acids in the water making the water too alkaline. Vise Versa. The lack of minerals or no minerals will make the water too acidic or even cause pH fluctuations once your once or during your aquarium is cycled.A side not - these minerals are also a source of nutrients for betta - Like us, fish need minerals for a healthy body.

kH and gH

kH, gH and pH are a trinity that go hand in hand.

kH and gH is the measurement of minerals in the water.

To correct this problem we need to implement a medium in your aquarium that will help slowly balance these minerals and thus raise or lower the pH. This is the safest method of altering these parameters during or when your tank is cycled or when your fish is added to the aquarium. The nitrifying bacteria or you better can suffer from any harsh changes in pH due to their biology. First though we need to test our mineral levels.

Start by testing your kH. Your kH is the most vital mineral to test in regards to achieving a stable and or appropriate pH. Although a very very high kH can be harmful. It must be noted that a low (or non-existent kH) can be even more so deadly for your fish. kH stands for (‘calcium hardness’) it can not only help stabilize a pH but provide the vital calcium which a betta will absorb to maintain bone growth for example. A kH up to 250ppm is absolutely fine for a betta and it will adapt even though it’s not perfect.

Using your API test kit, test your kH by adding one drop of the solution to your tube of aquarium water. Then shake the tube - how many drops of solution you add to the tube before the water turns yellow is how your kH is determined. Instructions come with the kit.

Even though the API chart stops at 12 you can still add drops to determine the dkH. 1 drop = 1 degree of carbonate hardness. For example 15 drops is = 267.9ppm. If your kH is, per se, off the chart though you will need to make adjustments.

The Right Way To Adjust Your pH

In the event that your kH is too low add some dried coral to your filter - adding crushed coral is also good but you may need to add it to a medium bag as it can be quite fine.This will slowly dissolve minerals into your water neutralising any acids and increasing your pH.

If your kH is too high we find adding a handful sphagnum moss to your filter acidifies to the water, slowly neutralising with the kH and lowering the pH.If you don’t want to add moss to your filter another great alternative is to add driftwood to the aquarium or indian almond leaves which we’ll get into later - but this will change the aesthetic of your aquarium and may turn the water a yellow colour.
If you do add crushed corals and sphagnum moss to your filter change every 6 months.

Why Test For gH?

So where does gH come in? Well gH stands for general hardness, these are other minerals, magnesium for example, that your betta fish also need to absorb like calcium in order for its body function. They also help with stabilizing pH. It’s always good to test your gH. Lowering or increasing gH is done in exactly the same way as lowering or increasing kH (crushed corals also add these minerals and sphagnum moss neutralises them). Like we said, pH gH and kH are a trinity that go hand in hand.If you have watched our section on cycling please progress to episode 7. If not step 5 is integral for setting up your aquarium so do go back and watch.

Treating / Dechlorinated Tap Water

The first thing you’ll need to do is pick up some aquarium treatment, also known as water conditioner. You’ll be able to get this online or from your local pet / aquatics store. Make sure it’s freshwater / tropical treatment. We use Tetra’s ‘Aqua Safe’. To use them properly you’ll need to know the volume of your betta aquarium. Water treatment usually takes 5 ml for every 10L.

Prepare your water in a clean container or bucket. Make sure the container hasn’t had any harmful substances, chemicals or cleaning agents in it. It needs to be completely clean. Rinse it thoroughly with tap water. Fill your container with the amount of water needed and the required amount of aquarium treatment. It will need to be left for an hour before adding to the aquarium.

Something else to consider are ‘biological enhancers’. These are bottles containing liquid that houses beneficial nitrating bacteria. Adding the liquid from the bottle to your aquarium water is supposed to help ‘kick-start’ the aquarium cycle. Whether or not it does so sufficiently can be debated – there have been differing reviews for various enhancers. We’ve heard Fluval’s ‘Cycle’ is meant to be a good enhancer, though. If you wish to add a biological enhancer, this is the right stage at which to add it. How much you’ll need to add per gallon will be noted on the bottle or any accompanying documentation.

Once an hour has passed, add the water to the aquarium. If you have substrate and ornaments set up in your tank, tip the water in slowly. Another trick you may like to try is to place a plate or flat surfaced object into the aquarium and pour the water onto that. This will stop substrate from dispersing when the water hits it. Once you have filled the aquarium accordingly, remove the plate and turn on the filter and heater. Leave the water to run for at least 48 hours before adding the betta; this allows the water to heat to the adequate temperature.

Note: To be extra sure the water is sitting at the right PH, you can test the water as described above. You can either do this by purchasing a PH testing kit (view the one we recommend here on Amazon) and testing it yourself or you can put the water in a small container and take it to your local pet / aquatic store where they may test it for you.

Examples of Water Conditioners:


Aquasafe Plus by Tetra (view it here on Amazon)

This has always been a reliable conditioner for us and helps get the water conditioners perfect for a betta.

Tap Water Conditioner by API (view it here on Amazon)

This is another option we've tested on our aquariums and been happy with.

You may like to read our article on how to change the water for your betta fish.