Hello,
Assassin snails will most definitely eat your shrimp. They can and will eat adult and baby shrimp. They are ferocious carnivores. They will eat anything they can catch, including fish, shrimp, and snails. I have only found one type of snail that they can't eat. I would tell you the type, however i have yet to positively identify what type they are. I have a post with pic. On here looking for help on this. If you are serious about breeding and raising your shrimp, then get the carnivorous snails out asap! I have had a large assasian snail kill and eat b.b. puffers! (Just for perspective). As far as fish are concerned, fish are opportunistic hunters and will eat anything that fits in their mouths. (This goes for ALL fish) Hope this helps!! Good luck!!
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Dave (>")>