Betta fish water: do’s and don’ts

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.

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. After reading this article, you may like to read our article on how to change the water for your betta fish.

Different types of water that you can use for a betta

So how do we get the ‘right’ water for a betta fish? Typically there are 3 sources you should go to to get your water:

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. It’s the most affordable way of acquiring water for your betta.

Read more about treating tap water below.

Bottled Water

Bottled water tends to be spring or mineral water. The pH of bottled water varies depending on the provider, so it’s best to test the water with a pH kit. If the water has an adequate level of pH for a betta and it is clear that the water is from a natural source, you can avoid treating the water. Like any other aquarium water, allow it to run through a filter for a week or so and warm to the right temperature before introducing it to your betta. A perk of bottled water is that it can contain some really beneficial natural minerals that are great for your fish.

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 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 of 7.0. 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.

Test kits usually come in 2 forms: strip tests and tube tests. The strip test is simple, 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.

The tube test kit is similar. 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.

What if your pH level is not right?

If you purchase a full kit, they usually come with pH adjustment chemicals. If you find that the pH of your aquarium is not at the right level, you can use these to correct.

Add drops of the ‘pH up’ to the aquarium to increase your pH level.

Add drops of the ‘pH down’ to the aquarium to decrease your pH level.


How many drops that you need to add per litre / gallons to get to the desired level will be indicated with the adjustment chemicals or with the kit documentation. Once you add the drops, wait 48 hours and then test again. If it hasn’t reached the desired level, repeat this process until the correct pH level is met.

Quick Tip: sometimes aquarium driftwood and rock can gradually change the pH of your water; not always by a lot, it does depend on the type and quality of wood and rock. Driftwood tends to lower the pH and rock tends to increase the pH. Not all rock increases the pH though. We also talk about this in our decoration ideas article.

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’ or ‘Safe Start’. 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 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.