Freshwater fish use osmosis to drink water, that is, they absorb the water through their skin.  Saltwater fish actively drink water through their mouths so their gills can remove the salt.   Salmon can do both, because they are both freshwater and saltwater fish.

And that’s why salmon are the best.

Your salary may come in the mail, but originally it comes from the Latin adjective salarius, meaning pertaining to salt.  Roman soldiers used to receive a handful of salt everyday.  Eventually the salt was replaced with money, and the soldiers could go buy as much salt as they wanted.  Money is a good thing, especially with my high blood pressure.  If I just got handfuls of salt all the time, I probably would just quit working.  Especially considering the fact that I have big hands.  I would be getting way too much salt.