I have three adult Assassin Snails in my heavily planted BIOCube 14. A week ago I noticed one of them was always attached to the shell of another. This morning that pair was i the front of the tank and there was a baby snail attached to them. I don't do anything to encourage their breeding or even their survival. They have to scavenge for a living. I can't remember when I last saw another snail in that tank other than a pair of Nerite Snails