Does Aquarium Salt Kill Plants?

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Aquarium salt is beneficial for freshwater fish since it improves gill activity and functioning, allowing fish to breathe better.

It also promotes mucus production, which aids in wound recovery and boosts the fish’s coloring and overall health state.

The problem is that adding salt to a planted tank could backfire. Some types of salt aren’t meant for planted aquariums, while some plants are sensitive to most salt types. Which brings us to today’s topic – will aquarium salt kill plants?

Is Aquarium Salt Safe for Plants?

The answer depends on the type of salt you’re using and the plant in question. Not all aquarium plants will tolerate salt as easily as others.

For instance, API salt is the most commonly used product for helping fish deal with parasites, enhance their physiological functioning, promote healing, and improve breathing and biological activity.

API salt is essentially evaporated sea salt and contains naturally active ingredients, making it safe for all forms of aquatic life.

However, as we will soon discuss, some types of salt may not be safe for your aquarium plants.

And even with the safer alternatives such as API or Epsom salt, you should always assess your plants’ health in the long run.

Some plant species are naturally sensitive to some salt types or salt in general. If you notice your plants exhibiting signs of distress (hindered growth, browning, signs of death), you should eliminate the salt immediately.

A larger water change may be necessary to dilute the salt fast and effectively.

How Much Salt Can Freshwater Plants Handle?

This is too much of a broad question to answer decisively. Instead, I recommend testing the waters (heh) yourself.

For instance, if your freshwater fish require salt treatment, 1 tablespoon of salt per gallon of water is considered very high. Some fish may be able to handle and even require that, some not.

For most fish, you should use a concentration of 1 tablespoon or less of salt per 3 gallons of water. This concentration should be safe for most freshwater plants unless evidence suggests otherwise.

If your fish and plants tolerate that concentration well, you can increase the amount of salt slightly and watch their reaction again.

When it comes to treating freshwater fish for parasites, infections, or other diseases, a concentration of 1 tablespoon for 3 gallons of water is often sufficient. Just keep in mind that not all fish can handle even this low concentration.

Some catfish species are particularly sensitive to aquarium salt, so you should discuss it with your vet prior to administering any amount of salt to their habitat.

You should then supervise your fish and plants for several days to a week. If the fish’s disease doesn’t improve, increase the salt concentration slightly.

If your plants show signs of discomfort due to the increased salt concentration, move the fish into a hospital tank. This will ensure optimal care without disturbing the plants in the process.

Aquarium Plants That Can Tolerate Salt

There are several aquarium plant species that will tolerate higher salt concentrations than others.

These include:

  • Java fern – This is a slow grower that only requires low lighting and can thrive in a wide range of temperatures (55-85 F). This plant is resilient and will adapt to anything life might throw at it, including fish aggression, poor handling, or inconsiderate aquascaping that will have the plant glued onto various surfaces. This is a brackish water plant, so it will tolerate more salt than most other species.
  • Anubias – This is another plant species capable of adapting to brackish environments with relative ease. Just like java fern, anubias can tolerate a wider range of temperatures and doesn’t need high lighting to thrive. Anubias is a great addition to any tank setup, including those with herbivorous fish. Despite the plant’s more fibrous matter.
  • Cryptocoryne wendtii – This species will handle mild salt conditions quite well, making it great for brackish environments. Just like the previous 2, cryptocoryne is an excellent choice for a variety of temperature and lighting conditions. However, this species is more demanding in terms of substrate quality. You may need to use a substrate fertilizer to ensure optimal growth and long-lasting health.

These plants make for great additions to a brackish environment, so long as the salt levels remain mild.

How to Treat Your Fish Without Salt?

I would say that there are 3 primary treatment methods to consider if adding salt to the tank isn’t an option:

  • Quarantine the fish – This is a trickier one because it presupposes you already have a hospital tank. If you don’t, you should prepare one just in case your fish experience health issues at some point. Quarantining the fish is the safer option because it spares your plants from the effects of salt or antibiotics that you may use during the treatment. Just make sure that the hospital tank emulates the main tank’s environmental conditions to prevent temperature, pH shock, or any other problems.
  • Use salt-free conditioners – These are available for freshwater exclusive use. Salt-free conditioners are great for treating fish that cannot tolerate salt or for using in heavily planted tanks. Remember, most tank plants don’t do well with higher salt concentrations. And you may need to use more salt in some cases to address certain infections or parasites. A salt-free conditioner is gold in such situations.
  • Use medications instead – This isn’t a universal recommendation but rather a circumstantial one. In other words, certain conditions don’t need salt treatment at all. This includes fungal and bacterial infections. You treat those with antibiotics and other antibacterial medications.

Other treatment methods include raising the tank’s temperature and using disease-specific medication to address the disease in question.

The temperature increase is mostly effective against parasites like Ich and other organisms that cannot survive at temperatures above 80 F.

Just make sure that the fish can tolerate those temperatures before starting the treatment.

I would say that the best way to do it is to quarantine the fish first. The length of the quarantine period typically varies between 1 to 2 weeks, depending on the disease’s profile, severity, and your fish’s recovery rate.

Doing so will not only ensure better treatment for your fish but will also protect the other fish in the disease is contagious.

And, naturally, protect the plants against the salt or different medications you’re using during the treatment.

Will Aquarium Salt Kill Algae?

Yes, aquarium salt will easily kill algae in high-enough concentrations. After all, algae are plants and won’t cope well with pretty much any salt content.

So, based on this, it turns out that using salt to get rid of algae is a legitimate algae-repelling method, right? Not.

The problem is that algae thrive in freshwater environments, and having live plants coexisting with the algae creates a logistical issue.

The added salt will also hurt the plants in the process since both algae, and the live plants operate based on identical principles.

So, you can only use aquarium salt to treat fish-only tanks. Once you introduce live plants, the whole system changes, and so must your approach.

Will Epsom Salt Kill Aquarium Plants?

Epsom salt will kill aquarium plants, but the problem is more complex than that. Epsom salt comes in 2 variations: regular and made for aquarium use.

The latter is safer for tank plants within certain limits.

Epsom salt is actually not a type of salt at all, but a mix of magnesium and sulfate, and it could actually benefit your plants to some degree. That’s specifically due to the magnesium content.

That being said, you shouldn’t rely on Epsom salt to provide your plants with magnesium since this salt isn’t exactly that effective in this sense.

You will be better off with a specialized plant fertilizer to provide the plant with various nutrients.

Can Aquarium Plants Grow in Saltwater?

Yes, some aquarium plants will grow in saltwater, but not all of them. Some popular saltwater plant species include green finger algae, Halimeda, sea grass, blue hypopnea algae, the shaving bush, red grape algae, and many others.

There are a lot of algae, as you can see, and that’s because most plant species don’t tolerate salt that well. If you have a freshwater tank, always be mindful of the quantity of salt you intend on using.

Most freshwater aquarium plants won’t tolerate even small quantities that are considered safe for your fish.

If you do need to use salt to treat your fish, I recommend the following 2 options:

  1. Rely on salt-tolerate plants – We’ve already discussed some of the hardiest plant species in this sense. We include here anubias, java fern, anacharis, cryptocoryne wendtii, java moss, and moneywort.
  2. Quarantine the fish – I keep coming back to this point simply because it’s the most reliable option when it comes to freshwater fish. Simply moving them into a hospital setup is enough to prevent all salt-related headaches. This is especially important, knowing that the treatment may last up to 2 weeks, and your plants cannot handle a higher-than-normal salt content for that long.

Lastly, we should discuss the salt-removing problem. This point shows why using salt in planted freshwater tanks is a bad idea all around.

Salt doesn’t dissipate naturally from the environment. So, you need to remove it manually via water changes, a procedure that will only remove some of the salt, not all.

If your tank has accumulated unsafe amounts of salt, you will need to perform regular partial water changes to dilute the chemical.

Performing a massive water change will hurt the fish or even kill them due to pH shock, temperature shock, or water demineralization. So, a 10% water change daily for about 1-2 weeks should fix the issue.

Naturally, the best option is to not use any salt for your freshwater tank, to begin with. But if you need to use it, at least ensure your plants can take it.


Aquarium salt will provide several benefits to your fish, as we’ve just discussed. The problem is that planted freshwater aquariums require a different approach in terms of salt use frequency, salt content, and the type of salt you’re using.

Keep the salt levels to a minimum and consider quarantining the sick fish should you need to use higher amounts of salt during treatment.

If your plants exhibit browning or dying leaves assess the salt levels, perform water changes, and even relocate the plant into a different environment until the situation is fixed.

Author Image Fabian
I’m Fabian, aquarium fish breeder and founder of this website. I’ve been keeping fish, since I was a kid. On this blog, I share a lot of information about the aquarium hobby and various fish species that I like. Please leave a comment if you have any question.
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