When |I see a thread on how to eradicate/reduce small snails like Malaysian Livebearing, I always first ask "why?" These snails are you best friend in any aquarium; they can get everywhere to eat the organics, breaking it down faster for the various bacteria. They are actually a sign of a healthy tank.
If you think you have too many, consider that they will only exist so long as they have food. This can be overfeeding of fish, or overstocking fish in the tank. The "food" of these snails is everything organic that is dead, like fish excrement, fish food in excess, etc. If this is a problem, reducing the snails is not a good move.
Assassin snails are not the best answer; if these should happen to get into the natural eco-system they can eradicate the native snails to the extreme detriment of the eco-system.