I watched it kill one of my cherry shrimp but couldn't do anything. One my of shrimps molted and I thought it's a good sign, but then later I saw this snail attack my shrimp, my shrimp was defenseless and couldn't run. I try to help him immediately but the snail won't let go and the shrimp died...
I took all 4 of the snails out, crushed their shell and feed them to my turtle.
They look like ordinary pond snails from the Physa family. They don't attack or eat healthy shrimps (not sure that any snails do). If the snail attacked a shrimp it must have already been dead/dying or t would have simply moved away.
Are you sure the snail was attacking the shrimp and not its moulted exoskeleton? Shrimp usually hide after a moult until they harden off again.
Yep, it's that snail. These one are really big, twice bigger than the shrimp.
My shrimp was healthy and I only see one exoskeleton at the moment. Ammonia,nitrite is still 0.
First I saw the shrimp was still sitting in plants but then when the snail came, I thought it was just passing by so I look away, after a few min, I saw the shrimp was struggling. It moves rapidly exactly like the way when it got chase but couldn't get away from the sticky snail. I tried to help it by picking the snail up but the snail won't let go until I took both of them out of water. The snail is already dead and it's really soft at the time. a piece of red skin under the head was missing and show white meat there.
I'm afraid I'm still inclined to think there was a pre-existing problem with the shrimp. I have never heard of any snails like that taking healthy shrimp - even Assassin Snails won't usually take live, healthy shrimp and shrimp can always move faster than a snail. There is something else going on here (IMO).
Have you tested the water in the tank? Test and make sure you have no ammonia or nitrite. Make sure the temperature is suitable. If all that checks out OK wait at least a week and watch for any signs of ill-health. If they all seem well then, you can add some more, though if you spot any of the females looking ready to produce eggs you can just wait for the shrimplets to develop rather than buying more.