Are Snails Good For Your Tank?

[bluesword23516]

So I recently bought some plants from another tank owner and he had some snails. Are the snails good to have? Or should I get rid of any snails that I see? 
I also bought some red cherry shrimp, I have a fairly aggressive fish, a white skirt tetra.  She has nipped at them a few times, but could never get them in her mouth.  Do you think she will leave them alone? 

 

[attibones]

If you get more white skirts, you'll have less of an aggression issue, though this species is, in general, fairly nippy.

A few snails don't hurt, but many people remove the snails because they are prolific breeders and can take over a tank. They poop a ton, so the more you have, the more you have to worry about that nonsense. They can be pretty good at cleaning up any diatoms, but I think some will eat on plants. I'm not sure about that though. It's just when I have an excess of snails in my planted tanks, I see a bunch of little holes in my leaves.

 

[the_lock_man]

Opinion is divided on this.
 
Some people like to have a few pond snails, as they can be an alarm system - if you see them all scooting to the top of the tank quickly, there's an ammonia issue. If the population explodes, you're feeding too much.
 
Personally, I hate them, and have eradicated them using assassin snails.

 

[Baccus]

Some snail species can have a place in a tank, be it nerite, assassin, trapdoor, apple or mystery, this is because they have a use in that they will eat algae left over food and even any dead plant material and are easy to control their numbers because either they cant breed in fresh water successfully or only have limited numbers of offspring or eggs in easy to remove places. However the vast majority of most of your pest snails are eating and breeding machines, laying eggs it seems on every surface of the tank, I have seen the pest snails in my tanks swarm over foods meant for either my catfish or shrimp so thickly that the desired species I wanted to feed don't get a look in.
 
I have now come to an arrangement I can live with in my tanks, when ever and where ever possible I remove as many of the pest snails as I can physically and in their place I introduce species of snails that I do want to keep.