guppies and salt

I have a few guppies and a betta in one of my tanks, the lfs told me to add salt to the water as guppies like that. Will this hurt the betta? also what sort of salt do I use and how much for a 10g tank? thanks

Hmmm - most livebearers love salt in the water - guppys, well lets put it this way: a little to much salt will split their tails - same goes for the bettas .......... Frank

Forget the salt. Guppies are freshwater fish requiring only appropriate nutrition and a well maintained aquarium.

Guppies are found in abundance over here in Malaysia even in polluted drains, they are extremely hardy.Although the addition of small amounts of salt, I believe should not do any harm however I do feel is unnecessary.
They were introduced here by the British a long time ago to control the mosquito menace, the effectiveness till today is debatable.

Here in the desert they put mosquito fish in ponds and other still waters like deserted swimming pools. They look like guppies without nice colors, and they do eat mosquito larvae. Maybe the people who tried to impose western culture on Malaysia were not as smart as they thought they were.

It was the state of the art solution at the time,environmentaly safe but maybe not ecologically so but the alternative was to use DDT.
DDT was used anyway till the late 70's when it was found to be too toxic with questionable biodegradebilities.
I used to catch this wild guppies as live food for my ever hungry Oscars when I had them years ago.

It really is not necessary to add any type of salt in with the guppies or the betta unless you are treating the fish for torn fins.
The salt will help heal wounds, etc.
The only kind of salt you would use would be Aquarium salt ( or Sea salt)..which most LFS carry.
DO NOT ever use iodized salt.
Use 1 TBSP. per 5 gallons.
Best thing to do( for healthy fish) is do frequent water changes.
Also..if these are "fancy" guppies..your betta just may find them a "target"...so I would be extra careful to make sure there is no aggression.