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Once again, we are going to discuss a controversial topic in the betta hobby: the use of aquarium salt. Despite offering many benefits—such as being cost-effective and easy to use—it still has specific side effects. However, its advantages often outweigh the drawbacks, making it difficult to ignore entirely. The usage of aquarium salt can vary widely and is usually not clearly explained. The ongoing debate surrounding its use highlights a lack of knowledge among betta owners regarding proper guidelines and considerations.
Is Aquarium Salt Safe for Bettas?
Aquarium salt is not inherently harmful to bettas when used correctly. Per the recommendations of a paper published in ResearchGate, betta fry can tolerate salinity levels up to 5 ppt. Adult bettas surely will accept higher salt concentrations as they are less sensitive than betta fry.
Unlike table salt, aquarium salt is free from iodine and unnecessary additives, making it a safer choice for aquatic use. However, to be on a safer side, if your betta is all doing well—don’t add it to the tank. It’s only recommended for medication purposes.
Benefits of Aquarium Salt for Betta Fish
1. Helps Control Pathogens and Parasites
Aquarium salt creates an environment less favorable for harmful parasites and bacterial. It can help manage outbreaks of common fish diseases such as ich and velvet.
2. Boosts Slime Coat Production
Aquarium salt stimulates the slime coat around the betta’s body, helping them to resist infections.
3. Reduces Ammonia Toxicity
Ammonia exists in two forms: toxic-free ammonia and safer ammonium. The ratio depends on pH, temperature, and salinity. Increased salinity lowers the level of harmful free ammonia — an important factor for tanks with high pH and warm water.
4. Promotes Osmoregulation
Osmoregulation is the process by which fish maintain a proper balance of salt and water in their bodies.
Freshwater fish like bettas constantly absorb water through their skin and gills, so their bodies work hard to expel the excess.
Adding aquarium salt slightly increases the water’s salinity, easing the fish’s osmoregulatory load, which helps them conserve energy and recover faster from stress or illness.
5. Protects During Nitrogen Cycling
In newly cycled tanks, bettas are vulnerable to toxic nitrate and nitrite intake. Aquarium salt can provide a buffer, preventing the absorption of harmful compounds.
6. Supplies Electrolytes
Essential electrolytes found in aquarium salt promote proper nerve and muscle function in fish, contributing to their overall vitality.
Common Misconceptions About Aquarium Salt
1. Salt Stresses Freshwater Fish
Salt stresses freshwater fish only at higher concentrations. Bettas can tolerate low to moderate doses of aquarium salt. Using the right concentration, not overdosing it, highly benefits your betta fish.
2. Salt is Always a Cure
Salt can help treat mild to moderate infections. However, it does not mean that it alone will always fix the underlying problems. It’s not a universal solution. Many illnesses, such as internal parasites and severe bacterial infections, like fin rot, require targeted medications. You can also use salt alongside medications like methylene blue or antibiotics in separate treatment baths.
3. Salt Can Be Filtered Out
Unlike medications, salt does not break down or get removed by filtration. It must be diluted via water changes. Repeated dosing without tracking salinity can lead to harmful buildup. Hospital tank use is ideal to avoid long-term exposure in the main tank.
Methods of Treating with Salt
1. Salt Bath (Short-Term, High Concentration)
A salt bath is the most commonly used salt treatment method. This method involves adding a higher concentration of salt to a separate container and dipping the betta into it for a shorter period, depending upon the severity of the infection. Salt baths are used for quick and aggressive treatment of external issues like parasites, ich, mild bacterial or fungal infection, or even early fin rot.
Usage Instructions
- Dose: Use 1 tablespoon of aquarium salt per 1 gallon (approx. 3.8 liters) of de-chlorinated water.
- Temperature: Match the tank temp (usually 78–82°F or 25.5–28°C).
- Duration: 10–15 minutes max.
- Frequency: Once per day for 3–5 days (max 7).
- After the bath, place the betta in a separate quarantine tank (not back in the main tank), especially if the illness is contagious.
- Never reuse bathwater.
For Epsom Salt (for bloating or swim bladder)
Don’t confuse Epsom salt with regular aquarium salt, as they serve different purposes. Epsom salt is used to cure bloating and swim bladder issues. Other instructions are the same as for normal aquarium salt.
2. Salt Dose in Hospital Tank (Long-Term, Lower Concentration)
This method involves adding the salt directly to the quarantine tank and keeping the betta in it for several days.
Usage Instructions
- Dose: 1 teaspoon per gallon (not tablespoon) of aquarium salt. For a tablespoon, use the salt in the proportion of 1:3 (for 3 gallons of water, use 1 tablespoon of salt).
- Only increase, if needed, to a maximum of 1 tablespoon per gallon. This must be done gradually and never in a planted or main tank.
- Do daily 100% water changes and re-dose accordingly.
- Duration: 5–10 days, depending on the issue.
What’s the Best Method?
Not all salt is the same nor every method works for each problem. Using wrong type of salt can do more harm than good for your fish.
- For early fin rot, mild wounds, stress relief, or external infections → Use aquarium salt baths.
- For bloating, constipation, or swim bladder → Use Epsom salt baths.
- For serious cases → Combine bath with a hospital tank + observe.
Dosage Guidelines During Water Changes
Salt does not evaporate, so you only need to replace the amount lost during water changes. For example, if you’re dosing salt in a 20-gallon hospital tank and perform a 25% water change (i.e., remove 5 gallons of water), you should only add salt for the 5 gallons being replaced. If you’re using 7 tablespoons of salt for the full 20 gallons, then after removing 5 gallons, you would add back 2 tablespoons (or less) of salt to maintain the correct concentration.
When to Use Salt
Salt is recommended mainly for diseases caused due to external parasites such as ich and velvet. It also gives good results for mild fungal or bacterial infections like early fin rot. You can also use it as a preventative measure, such as slime coat protection. In a few countries like Canada, some fish medications are restricted, so you can use salt as an alternative.
When to Avoid Salt
There are certain areas where usage of salt should be avoided like the below ones.
- Internal infections (salt is ineffective)
- Planted tanks (salt can harm live plants)
- Long-term use without monitoring (risk of salinity buildup)
Common Precautions and Guidelines
Plant and Fish Sensitivity
Aquarium salt can affect most live plants. Therefore, it’s advisable not to add salt directly into a planted tank. Similarly, high salt levels can harm sensitive species such as:
- Corydoras catfish
- Chinese algae eaters
- African Dwarf Frogs (especially during shedding)
If you’re adding salt to a community tank with sensitive inhabitants, do it gradually over a few days and stay within safe limits.
Don’t Use Table Salt or Sea Salt
When we speak of aquarium salt, it does not mean table salt or any other type of salt. Table salt contains iodine and anti-caking agents, which can disrupt the aquarium’s biological balance. Similarly, sea salt includes trace minerals not suitable for freshwater species.
Some also use Epsom salt instead of aquarium salt for specific cases like bloating. Don’t mix aquarium and Epsom salts unless directed by a vet.
Potential Harm from Long-Term Use
Aquarium salt should be used in the specified dosage for freshwater fish like bettas. Many betta experts have noticed that prolonged exposure to aquarium salt harms bettas by disrupting their osmotic pressure. This imbalance may lead to dehydration, further stressing the fish. It can also shrivel bettas’ fins. So, long-term exposure to saline conditions is unnatural and possibly harmful.
Our Final Perspective
No natural freshwater environment is completely salt-free — even rivers and streams in Southeast Asia (home to wild bettas) contain trace amounts of salt. However, high rainfalls in these regions may dilute the salinity level. The careful use of aquarium salt can mimic that natural environment more closely and support reducing stress, promoting healing, and maintaining health.
Always research, start with low doses, and adjust based on the needs of your fish and tank inhabitants.
