I just wanted to know if I can keep apple snials and shrimps in my 30 gal. goldfish tank that has aquarium salt added to it.

I forgot to ask another question. If I can keep them in my aquarium, would I still have to qurantine them for at least a month?

no, snails and shrimp dont tolerate any salt. sorry

Why did you add salt into the tank? You should maybe do a water change
and get that salt out. And add the snails and shrimp back.

Snails and shrimp can handle a small amount of salt but not alot.

Alex