Ok so I got some mystery snails and one of them seemed to be off from the time I brought them home. He didn't move much but he did a little and I did see him eat. Past few days he's just been in his shell so I decided to give him a few day cuz I did just add stuff to their tank and he might just be stressed. But today I did a smell check and he smelled horrible and the little trap door I believe it's called just slid off. So my question is do I need to do a complete whole tank cleaning or what? It's my first time having any kind of fish or aquatic animals and I don't want the others to get sick.