By "freshwater salt" I mean salt specifically made for freshwater aquariums.
Thanks!
This is rubbish. No, really, it is. Hear me out. You should never put something in your tank without a specific reason. To have a reason, you need to know what the item is. Does it have a list of ingredients? I'll be surprised if you say yes, because none of the 'aquarium salt' for freshwater products that I have looked at include a list of ingredients. They all have claims for what they DO...but no ingredients. So, how can you buy into the idea that freshwater NEEDS this salt? If you don't know what is in there, how can you monitor it? How can you tell it's doing anything?
Salt has it's place--but table salt works fine for treating parasites. Livebearers benefit from hard water more than from salt.