HI there my frind had a tank wich he has had a snail in for about a year or so and it was doing fine until he aded a trapdoor snail in the tank. the next mornign they were both dead. water perametersd are fine and the trapdoor was moving around the first nite. any ideaas what happed? we wer wonderign if there could ahve been some sort if diseas it may have spread to hes previous snail. were jsut curious why the one that was in there previous would die aswell. its a 45g tank with a large community of fish aswell. thank you.