Why did snails die? I got some snails from outside and took them home and was going to make them an aquarium later their antenna arent sticking out and the edge of the shell feels thin. I feel terrible because i should have let these animals be

Don't feel terrible. Your heart was to give them a good home and take good care of them. You have a big heart and I think this is sweet of you. My thoughts are.... Now get on the internet and learn about these particular snails. Learn what temperature they are accustom to. What do they eat? Do they need leaves and sticks in their habitat or are they water snails? The more you know, the better chance others have of surviving. Or you can let these ones be and get snails from a pet shop maybe? Good luck. :0)