Can Tetras Live In Brackish Water? (Is It Safe For Tetras?)

Image of a tetra living in brackish water

Tetras are freshwater fish. Now, you may wonder how this common household fish would hold up if you kept them in a brackish water tank. Would it perish, or would it adapt to the change in salinity? So, can tetras live in brackish water?

Yes, tetras can live in brackish water. Most types of tetras can tolerate salinity to an extent. However, they won’t survive in pure saltwater. They can tolerate tank water with a salt content of 1 tablespoon per 2 gallons only. X-ray tetras are an exception as they can thrive in very hard water.

Let’s talk about this in detail now…

Ideal Water Conditions For Tetras

Tetras come from the rivers and streams of South America. The water here is soft and acidic with a pH between 6.8 and 7.8 and a temperature range of 75°F to 80°F.

Although tetras live in rivers, they are usually found in areas with low to moderate currents. You will find them in river basins with slow-moving water.

Although tetras are quite tolerant of an increase in water salinity, sudden and drastic changes can adversely affect them. A significant increase in salinity can affect their reproductive ability and make them vulnerable to illnesses.

How Are Brackish Water Tanks Different?

Although freshwater aquariums are very popular with fish hobbyists, they may choose to keep brackish water aquariums for certain reasons.

Experienced fish hobbyists prefer brackish water tanks because it allows them to keep exciting species of fish. Some fish, like archerfish, spotted puffers, and the Colombian shark fish do poorly in freshwater. But they live for years in brackish water.

In the wild, such fish are usually found in estuaries where rivers meet the sea. Saltwater from the ocean mixes with the freshwater of the river in these areas. So, the water will be saltier than freshwater but not as salty as seawater. 

So, these types of fish will do best in a brackish water tank.

The salinity of brackish water is between that of freshwater and saltwater. Now, we can divide brackish water tanks into different types based on the level of salinity. Nonetheless, brackish water tanks will always have a salinity between 7.2 and 8.5 and a specific gravity between 1.005 and 1.012.

Maintaining brackish water tanks requires more expertise than a freshwater tank. Apart from good filtration, you will have to change 10% of the water every week or 25% of the water every two weeks.

You will also have to treat tap water with a salt of proper concentration before refilling the tank. For this purpose, you will need additional equipment to monitor the salinity levels. It can also be more expensive.

Now, some aquarium owners prefer to keep freshwater fish with the species that come from brackish water. In some cases, they may also consider transforming a freshwater aquarium into a brackish water aquarium to accommodate fish that need such water.

Before converting a freshwater aquarium into a brackish water tank, you should consider how this change will affect your freshwater fish. True freshwater fish may perish in such tanks. So, let us find out what happens to tetras when you do such a change.

Recommended Further Reading:

What Happens When Tetras Are Kept In Brackish Water?

Tetras are found in freshwater in the wild. Nevertheless, most aquarium owners keep them in water with higher pH in captivity.

It does not cause a problem as tetras can tolerate a slight increase in salinity. However, the fish are sensitive to changes in water chemistry. Altering the salinity of the water beyond permissible levels can affect their health and well-being. Too much salt can make the fish sick or kill them.

Tetras can experience stress when kept in highly saline water. It can affect their bright and vibrant colors. Although the fish may not show obvious signs of stress, this change will affect their health and even reduce their life span.

Tetras do best in well-established aquariums with soft, acidic water. They will have bright colors and stay active and healthy in such settings.

Can Neon Tetras Live In Brackish Water?

Neon tetras are freshwater fish.

These fish do best in water with an acidic pH. Nonetheless, they are tolerant of brackish water. So, neon tetras will survive in water with moderate salinity. However, they will undergo immense stress if you increase the salinity beyond a certain level.

Neon tetras cannot survive in saltwater. Adding too much aquarium salt will make them sick. Prolonged exposure to high salinity levels can even kill this fish.

Hence, it is important to keep a close check on the ingredients you add to your tank. If there are chemicals that modify the water chemistry, it can adversely affect the tetra fish.

Related Further Reading:

Are There Any Tetras That Thrive In Brackish Water?

Although tetras can tolerate brackish water, it is not the ideal living environment for these fish. They will do much better when kept in freshwater settings.

However, the X-ray tetra is an exception as it can tolerate higher salinity levels. X-ray tetras will be fine in water with a pH level of 6 to 8.

This behavior has to do with the natural origins of the X-ray tetra. While most tetras are seen in the calm and slow-moving waters of rivers and streams, X-ray tetras live in brackish water in the wild.

They are abundantly seen in the coastal areas of South America. You will find harder brackish water in these areas and highly unstable water chemistry.

Since the fish can tolerate these changes, they are very adaptable and can survive in similar conditions in captivity as well. However, the X-ray tetra will also be fine in freshwater tanks.

Can Tetras Live In Saltwater?

All tetras need water with soft to moderate salinity to survive. These fish are very sensitive to changes in water chemistry. They will not survive if the salinity of the tank is increased beyond a certain level.

So, tetras cannot live in saltwater as it is an unnatural environment for the fish. If you put them in saltwater, it will be only a matter of time before they die.

Interesting Further Reading:

Is Aquarium Salt Safe For Tetras?

Aquarium salt is often used as a preventive or medication for a variety of fish illnesses. Many fish owners regularly use this ingredient to treat skin diseases caused by external parasites like bacteria.

Aquarium salt can be an effective remedy for skin infections caused by tiny bacteria and other microorganisms. When you dose the aquarium water with salt, it causes osmosis, due to which the fluid content inside the cells of these tiny organisms is sucked out, thereby killing them.

However, the tetra fish is not affected as much due to its larger size. Once the unfriendly microorganisms are killed, the fish have a better chance of recovery.

The chemical composition of this product is that of pure salt. So, it is unsuitable for fish that are extremely sensitive to even a small increase in salinity.

Nevertheless, you can use aquarium salt in moderation to treat tetras. They can tolerate it to a certain extent. So, you can use aquarium salt as a general tonic if your tetras show symptoms of skin infections. Stick to the recommended dosage of 1 tablespoon per two gallons of water for best results.