There are lots of myths and old wives tales surrounding the use of salt in freshwater aquariums. For many years, especially in the early days of the hobby, it was recommended to add aquarium salt as part of maintenance.
In recent years, however, this has flipped into never use salt in freshwater aquariums, but the truth of the matter is when salt is used appropriately, it does have several genuine uses.
Good examples for when you can use salt is when your fish has contracted a disease or an injury and when transporting or introducing new fish to your aquarium.
Some people will use it to treat fish together with medication, while others use it instead of medication.
Overall, the nicest thing about salt is how readily available it is, and how low the cost is compared to many of the medications.
So, to further demystify the mixup in facts and fictions, this article will delve a little deeper into the use of aquarium salt in fish tanks. We will look at how to use, when to use, and what kind of salt to use in your freshwater aquarium.
How to Use Aquarium Salt in Freshwater Tank
In my fish keeping practice, I only use salt for short periods, reserving it to when my fish are stressed or sick.
Moreover, I do not advocate for the use of salt in every situation. This is because there are some species of freshwater fish (scaleless), inverts, and plants (live) that are extremely sensitive to salt in water.
Too much salt will hurt such fish and plants or even kill them..
So, always research the animals you’re keeping before you decide to use aquarium salt in your fish tank.
Be that as it may, you might be wondering why adding salt in freshwater aquariums is important in times of stress, injury, and disease.
Intrestingly, fish have the same amount of salt concentration in their bodies as mammals, including humans. This amount is 0.9 percent, the same as in a line drip that is commonly used in human and veterinary medicine.
For fish to constantly maintain this level of salt in their body, they have to use up energy to excrete excess water that enters their bodies through osmosis.
So, if your fish is sick, stressed or injured, you’ll want to add salt in the fish tank to ensure the fish divert all energy towards healing rather than to maintain its osmoregulation balance.
What is Aquarium Salt Used For (Other Uses)?
As I mentioned, aquarium salt is used when you have injured or sick fish in a tank. Moreover, it is used when you have stressed fish particularly when recently transported or introduced into a new tank.
Howbeit, there are several other instances you may want to use salt in your freshwater tank.
Aquarium Salt for Osmoregulation
This is a term used to refer to the process of fish maintaining their body salt balance in a column of water, which is important even when your fish is not stressed or injured, though the stakes are higher when a fish is ailing.
Salt use is especially recommended for aquarists keeping fish like goldfish, livebearers, and African cichlids all of which have a high TDS (total dissolved salts) requirement to thrive.
To understand how osmoregulation works, you would have to take a step back to what you learned in your school days.
Basically, everyone was taught that osmosis is the movement of dissolved substances from an area of strong concentration to a weaker one through a semi-permeable membrane.
Hence, in the case of freshwater fish, which are saltier than the water they live in, and their skin act as a semi-permeable membrane, there is an apparent difference between the salt inside the fish’s body and the water column.
Hence, freshwater fish leak bodily salts and take in water, which presents two problems: maintaining the proper body salt level, and getting rid of excess water.
Luckily, osmoregulation works to create a balance, whereas adding small amounts of salt in the tank will help reinforce the equilibrium.
How to Use Salt as Treatment in Freshwater Aquariums
Aquarium salts can be a useful remedy for the prevention and treatment of several freshwater fish diseases. It assists in the healing of injuries, damaged fins, promotes the formation of slime coating, improves gill function, and is effective against bacterial, fungal, and parasitic infections.
A couple of years back, when freshwater cycling was poorly understood at best, fish also tend to suffer from nitrite poisoning (brown blood disease), and from then, it is was established aquarium salt can be used to treat this ailment.
Moreover, the filtration options both in filters and the media available were quite limited, so the addition of salt was (and still is) used, especially in the first few months of starting an aquarium, to keep parasites and diseases at bay.
Other times, fish maybe be affected by an ailment, which may cause the gills not to function properly. As a result, fish can experience osmotic stress by which electrolytes are lost through the gills, impairing the fish ability to take in oxygen and release carbon monoxide.
Freshwater aquarium salt, which contains beneficial electrolytes that replenish the lost ones, treat and restore gill function.
For this application, add one tablespoon of salt for every 5 gallons of water or per manufacturers recommendation.
When dealing with infectious elements, freshwater aquarium salt can also serve as a short-term bath treatment for external parasites such as Trichodina, Ichthyobodo, and Epistylis.
For such application, dissolve 2.5 cups of salt for every 10 gallons of water in a separate container, then carefully place the infected fish for 5 to 10 minutes, and then put the fish back in the main tank.
Repeat this process in 24 hours if necessary.
How to Add Aquarium Salt in a Freshwater Tank
When using aquarium salt in a freshwater tank, do not add it directly into the tank, make sure you fully dissolve the salt in a separate container of water before placing it in the tank.
This will keep the fish from coming into direct contact with the salt, which may cause burns, and more serious problems if the fish ingest it.
As I mentioned before, there are species of fish and plants that are really sensitive to salt. Some of them can handle low doses of salt for short periods, but overall, avoid dosing your water if you are keeping species like catfish, loaches, snails, most aquatic plants, and some invertebrates.
When using salt as a way to treat an ailment, start with the lowest dose possible because less is in some cases more. However, it might take a while before you see results, so you may have to exercise some patience.
Still on dosing, you’ll want to keep in mind that a finer grain salt will dissolve much faster than coarse rock-like salt. Moreover, salt does not evaporate from the tank and won’t be removed through filtration. The only way the salt will leave your aquarium is through water changes.
How Much Salt Should You Put in Your Freshwater Aquarium
The rule of thumb is to start with one tablespoon of salt for 5 gallons of aquarium water, which is considered a safe dosage for most freshwater fish and plants.
After this first dose, observe your aquarium for 24 hours to make sure if all is well. Howbeit, the application will give varying results depending on the intent with some results not too exciting.
Hence, when dealing with bacterial, fungal, viral, or parasitic infections, I would recommend using 2.5 cups of salt for every 10 gallons of water to bath the affected fish. Please note that this amount should not be added into the tank, but instead used in a separate container since most sensitive fish and plants can’t sustain that amount.
You may want to know how much of a specific salt to use. In which case, you should know the best salt for freshwater tanks is aquarium sea salt or Epsom salts if what you need is a laxative.
Use 0.7 ounces per gallon or 5 grams per liter of aquarium salt (sodium chloride) to help your fish maintain their osmoregulation balance in times of stress or ailment.
If you need to use the salt to get rid of parasites from fish, prepare a salt bath using 2.5 to 3.3 ounces per gallon or 20 to 25 grams per liter of sodium chloride (aquarium salt).
You can have your fish in this bath for up to 5 minutes.
Moving to Epsom salt, which is most commonly used as a laxative for fish, use about 4 ounces per gallon or 30 grams per liter for a 30 minutes fish bath in a separate container.
Alternatively, you want to add 0.1 ounces per gallon or 1 gram per liter for up to 30 minutes for a daily bath.
That said, most aquarium salts have recommended dosage from manufacturers at the back of the packaging. Use the advised amounts to start with and increase them appropriately as you observe the results.