Because of my fondness for mystery snails - a friend recently gave me her "sick" blue mystery snail with the hopes of me being able to help - however, I have never seen anything like this before and need some help figuring out what to do/what is going on!

From my understanding, she had this snail for about 3 months and it had been active and healthy until about a week ago. According to her, the snail remained upside down and inside its shell in the same spot on the bottom of the tank for about 5 days. Her tank is a 10 gallon with two mollies - who are pretty aggressive and liked to "annoy the snail".

I have now had her snail in my 1.5 gallon (I didn't want to put her in my 10 gallon in the case that she has something contagious) for the last 3 days. She stayed on the bottom in the same position for the first night - but yesterday started to come out of her shell a bit - but seemed to not be able to turn herself right side up - she even ate part of an algae wafer upside down. Today she was still seeming to struggle to turn herself over, so I helped her and put her right-side-up on the gravel and near the glass. She has now climed up to the top of the tank and I can see what the problem is - I just don't know it means. Her foot looks like it has been eroding, or a chunk has been pulled off, or it is some sort of fungus. I sent this picture to my friend and she told me that her foot did not look like this the last time that she saw it (about 8-10 days ago). I have been doing research all day, but have not been able to figure out what is going on.

Has anyone experienced something like this? Any advice? Please let me know if you need more pictures.

Thanks so much!