It depends what kind of tetra but mainly all do
No a snail can't live in a snail.
Yes, there are types of snail that can live underwater.
yes they will
No, clown fish are marine fish and tetra and guppies are freshwater fish.
Yes.
in the garden
love and snuggels
Yes.
because snail has a very slow metabolic rate
Yes but why do it?
Land snails live in ditches.
the snail the is best for your fish tank is the slowest snail that you can find in the store...the best snail i have had is the cuadrocnam snail so when you go to the store you say "I want is Cuadrocnam snail please!"