I inherited some of these cuties. I destroyed their whole colony and rescued four of them because the previous owner let them overbreed. But anyways here's some interesting info on them:
Courtesy of: http://members.shaw.ca/the-guyz/pest_snails.htm

In the Family Thiaridae, Melanoides tuberculata (Malaysian Trumpet snails) are the most common residents in our aquariums. These are hard-shelled cone shaped snails reaching an average of 2.5 cm in length. They have an operculum (door) on their shell, which serves as added protection against predators and adverse environmental conditions. They are live bearing parthenogenic females. This means that an unfertilized female can produce offspring. They are beneficial in planted aquariums because of their tendency to move through and literally plough the substrate. They spend most daylight hours busily searching for food in the substrate, and come out mainly at night when they can be seen on the sides of the tank.

So why would anyone want to keep these invasive pests?

In the above descriptions a few advantages, such as the Lymnea stagnalis’ appetite for hydra, have been mentioned. As a group what do these “pest” snails have to offer?

One big advantage is that they eat waste. Fish waste, extra food, decaying plant material, dead fish, unwanted or spoiled fish eggs and even other snail eggs. Yes, they produce their own waste too, but when they consume other waste products they reduce the amount of available “food” for algae, and aid the process of converting harmful waste to less harmful components.

A lot of smaller snails eat appreciable amounts of algae. Especially when other food sources are in short supply. Larger snails tend to eat larger food, therefore overlooking most algae.

Their population and behaviour are also indicators of aquarium health.

Elevated population indicate the presence of too much food. Not taking into account predators or other influencing conditions which will also affect the snails health and growth... Most snails are naturally regulated by food availability. When there is an abundance of food more of the hatchlings survive, they grow faster and reach maturity in less time. Continued abundance induces the adults to lay more egg clutches and so the cycle goes. When there is minimal excess fewer hatchlings survive, they grow at a reduced pace, and reproduce later and less often.

Snails need to breath. If water conditions are poor or oxygen levels are low they will move to the waterline in order to get air. They will remain at or near the surface until the adverse condition is rectified.

They are also a valuable live food source for some fish. When raised in the aquarium the occurrence of parasites that affect fish or humans is unlikely, particularly if the snails are from captive stock and are raised in such a way that the life cycle of potential parasites is interrupted. For example, by not providing the conditions or host necessary for further development.

Oh, and did anyone know that these are one of the few snails that won't destroy live plants?
Go here:http://www.fishpalace.org/M_tuberculata.html

I think i have a turmpet snail but i am not sure I only saw it once thou because it is such a little snail in a big pond i don't no if i will see it again you can look at my other post entiled Malaysian Trumpet Snail? for a picture

Yup trumpet snails are little cuties! lol...
Any way i heard they where great for cleaning tanks that have
sand in them.Im going to be getting some soon.

Too bad you don't live by me cause I'd give you some of mine....They just breeded again!

to bad,you live in ontario right?

No, I live in Alberta

Oh to bad thats rather far well not as far as the USA .... i live in Quebec canada,trumpet snails are know as pest snails right?

Yeah they are. I wish I would of known you when I was in Quebec last year! I would have given you some!