Do not put them with salt... even the tiniest, almost-not-even-there amount of salt or they will die. The smaller amount of salt, the slower the death... but it will kill them eventually. Other than that, they are very easy to keep. Just put in 1/4 of an algae wafer or a shrimp pellet every other day and they will do fine.
Actually, mine have lived in salt for a very LONG time and are fine. They can take it, and yes, they can also live in a filterless environment. They are pretty hardy unless up against a carnivorous ACF. Even the biggest of my shrimp turned into a snack for him.