They can eat fish food lettece carrots peas pretty much any fresh veggie
on how much to feed them it is sort of trail and error see how much they eat and feed them that amount daily
i don't no of any snail dieases
How much they live is based on your tank temp the higher your tank temp the higher the metabolism so their life cycle will speed up and they won't live as long like in 25C they will only live 1-1 1/2 years but in colder temps they can live 3 years
Apple snails have like a breathing tube called siphon that they extend out of the water to breath
You will no when u have a dead snail because an empty shell will be floating when they die they come out of their shells. If you see your snail floating don't panic that is normal they can even float for days as long as the floating shell isn't empty it isn't dead.
The easest way to tell the sex is to take them out of the water and turn them on their backs and when the snail comes out you have to look inside the right mantle cavity for the penis heath
for more info go to
applesnail.net