Can Guppies Live in Brackish Water? Can They Tolerate Salt?

Before you start preparing your tank, picking out decorations, etc. it is very important that you consider which conditions you would like to keep. Do you want a freshwater aquarium or a saltwater tank? Knowing the answer to this question will help you to decide a lot of things. 

For example, this decision will affect which fish and other creatures you can keep in your tank as well as any additional things that you will need to measure and maintain these tank conditions. The salinity of the water can be toxic for certain fish and so you will need to keep a careful eye on this. Even for fish that prefer brackish water, the salinity must be regulated.

So, here we will tell you everything that you need to know about guppies and brackish water. We will go through everything from the tank conditions that they need to other fish that they can live with in the same tank under the same conditions. 

Can guppies live in brackish water?

Although guppies can live in freshwater home tanks their natural environment is indeed brackish water. This means that their natural habitat is a mixture between freshwater and saltwater. An example of this type of environment is a swamp.

So, you can add guppies to almost any home aquarium and they will be perfectly happy it is still important to bear in mind that they will be most comfortable in a tank with brackish water. 

The specific gravity of the brackish water should be between 1.0005 and 1.010. For guppies, the ideal water density is at the lower end of this range.

Can they tolerate salt?

Yes, but although they prefer to live in brackish water there is no need to add extra salt to your guppies’ tank. Although this will not do your guppies any damage it may be a problem if you have any other creatures or fish in your tank. For example, if you have any snails in your home aquarium then do not under any circumstances add salt to your tank. 

However, if you want to add salt to your aquarium firstly make sure that your creatures can handle the increased salinity but also ensure that you use the correct salt. You cannot simply pour regular table salt into your home aquarium. In fact, experts recommend only adding marine salt into your tank. This can be found either online or in any good pet store. 

What fish can live in brackish water?

If you have decided that you want to keep your guppies in a brackish water home tank then you will want to make sure that the other creatures and fish that you choose to keep with them are able to tolerate the same conditions.

Here we will list a number of different fish that are able to tolerate the same conditions as guppies, but bear in mind that this does not mean that these fish will all get along. In fact, if you are considering adding any of these fish to the same brackish tank then you should do sufficient research to ensure that they will get along.

Fish that live in brackish water:

Do guppies like fast-moving water?

Guppies will naturally live in an area that has slow-moving water, although they are also able to thrive in a medium-level water flow. However, due to their small size, you should avoid placing them in fast-moving water conditions as this can cause problems for them. 

Guppies have long fins so they can move easily in slow-moving water. There is no need for them to be in fast-moving water for motility purposes as they can easily be swept up.

How do you maintain a brackish aquarium?

A brackish aquarium should only be maintained with hard water and have a pH level of between 7.2 and 8.5. The temperature should also be between 23 and 29 degrees celsius. You may need to install a heater in order to able to maintain these warmer water conditions.

Once you have successfully created your brackish water aquarium maintenance is relatively simple and will involve the basics such as feedings, filtering and cleaning. 

You will need to regularly scrape any algae that has built up on the sides of your aquarium in order to stop the algae from spreading and to keep your home tank clean. You will also need to occasionally stir the sand that sits on the bottom of your tank.

You will also need to keep your tank’s water clean by regularly changing it. However, you should not look to change more than 25 percent of the tank’s water at any one time as this can cause more problems than it solves. Beyond this, there is nothing out of the ordinary that you will need to do to maintain your brackish aquarium.


When choosing to have guppies in your home aquarium you can rest assured in the knowledge that your guppies are pretty robust creatures. They will withstand most salinity and environments. So, you can add them to your already existing tank even if it is freshwater or marine in nature. However, their ideal and natural habitat is brackish water.

You should ensure that the water flow in your tank is slow to medium as the guppies are only small in size. This coupled with their long fins means that they can easily be swept up in faster-moving water. Beyond this, maintaining your guppies in their tank is not a particularly demanding task. 

You can add salt to your brackish water home tank if you need to, for example, to help cure illnesses, but there is no need to. Your guppies will, however, be able to tolerate this extra salinity.

You should ensure that you are adding the correct type of salt if you do so, i.e. only add marine salt that you have purchased from a reputable aquatic store and not regular table salt.

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