I guess it depends on the fish. A lot won't eat adult shrimp but will definately have a go at babies. Some despite being small fish may attack shrimp in groups, just like a wafer. Certain species of gouramis do that.
From all my fish I can guarantee that my cories won't touch any shrimp at all. Almost microscopic shrimp eat alongside grown up corys, and even take a ride on them.
The easiest and undemanding shrimp are the Neocaridina species. There are a lot colour varieties of them, the most famous being the cherry shrimp but there are rili(red/blue), yellow, blue, mandarin, sakura orange, etc.. whatever you prefer. I treat mine(cherries and red rilis) just like fish, no special treatment, extra care/extra testing and they breen like snails.
I would definately drip acclimate them when introducing to the tank and depending on how many you initially get it may take several months for them to establish a good colony.
Good luck. Shrimp are great and very active if given the right enviroment.