Aquarium Salt: When to Use It (and When Not To)
A useful tool that's often misused.
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What it does
Aquarium salt can help treat some parasites and reduce nitrite toxicity in an emergency. It is not the same as marine salt and does not make a freshwater tank 'brackish.'
Use sparingly
Many soft-water fish (tetras, corydoras, many catfish) and most plants dislike added salt. Use it as a targeted, short-term treatment, not a permanent additive.
Remove with water changes
Salt doesn't evaporate — it only leaves via water changes. Dose carefully to the label and don't keep topping it up.
FAQ
Should I add salt to my freshwater aquarium?
Only as a short-term treatment for specific issues. Many fish and plants dislike it, so it's not something to add routinely.