How Apple snails save the Pantanal from the floods - with the help of their secret weapon, a snorkel!
More about this programme: http://www.bbc.co.uk/programmes/b01kvm72
The apple Snail
Ampullariidae, common name the apple snails, is a family of large freshwater snails, aquatic gastropod mollusks with a gill and an operculum. This family is in the superfamily Ampullarioidea and is the type family of that superfamily.
The Ampullariidae are unusual because they have both a gill and a lung, the mantle cavity being divided in order to separate the two types of respiratory structures. This adaptation allows these snails to be amphibious. http://en.wikipedia.org/wiki/Ampullariidae http://www.applesnail.net/
I had one in my tank, 3 months later I had near 200. Don't add to aquarium.
I added the smaller snails for my cichlids to crush and they multiplied by a thousand in like two or three days. All over my filters too...it was a PITA to get rid of them.