Snail newbie

So I recently adopted this big jar from my housemate with 6 snails living in it and a couple little worms.

I did a little research and found out you can feed them all kinds of unprocessed foods, I threw in a slice of cucumber. The next morning the water was unclear (picture 2). Is this something i should worry about?

Besides this, does anyone know what type of snails these are and how they should be kept? Do I even need to feed them? Do they need to have their water changed? Is tap water fine?

Any help is appreciated, thanks!