Each life's personality is different, maybe you have too much food in the tank assassin snail didn't need to take chance on shrimp. Perhaps your assassin snail did eat 1 or 2 shrimps however you never witness it. There is no right or wrong in this situation, we all adjust stuff base on other and our own experience. Cammywf witness the situation and he will adjust it. I believe he did have ramshorn snails in the tank, those might already be eaten by assassin snail or gone hiding.
That is exactly my point. There is no right or wrong. But I was pointing out normal scientific observation. Nature designed snails and shrimps to be both scavengers but shrimp also catch other microorganisms while snails normally do not unless they are diseased or dead. I would also argue I do not feed too much food or my tank would be full of dead organisms. I feed
enough food. So removing the snails if there are no snails or feeding enough food if there isn't sufficient food would test that theory wouldn't it?
Have my snails eaten shrimp? Perhaps. But I can tell you for a certainly that hundreds of shrimp have died of old age and have been eaten by BNP, snails of all kinds (hence the reason I keep Assassin snails) and other shrimp. I see shrimp being eaten by other shrimp all the time. Every day in fact. I'm sure I can get a photo today. However, does that mean they hunt their own kind? Of course not, otherwise my population would be very limited indeed. So my point was just because people have observed on behaviour, doesn't mean they have observed or recorded circumstances leading up to that behaviour. But wouldn't you agree snails also are not born knowing Assassin snails would be their predators and that they are easier to catch than shrimp. So then why would they catch a shrimp?
Again, I am not here to argue this one instance, but rather, I don't want people being discouraged from keeping shrimp and Assassin snails together in the same tank because there have been reported instances of predation, that's all.
If you or anyone else are not comfortable keeping your shrimp with Assassin snails, by all means, separate them. My objective is not to tell you or cammywf what to do. It is to provide another viewpoint from personal experience so that others reading this forum can make their own decision.