Only salt I use fer smokin is kosher salt. Other salts can be used but ya gotta remember, kosher salt measures out different then table salt due ta the crystal size.
Don't use regular table salt if its been iodized cause it can give ya a metal taste.
If ya got no salt, I'd skip it cause ya ain't brinin, takes salt in the water to transfer the flavour deep inta the meat. Ya be better off ta season it an give it a hotter faster cook in my opinion. Now my opinion an 50 cents get ya a cup a joe at jeff's diner!
Fish bein thinner an such ya should have no problem gettin some smoke flavour in there an gettin it cooked up in a decent amount a time.