Male yeast infection from swimming in dirty water?

Question

My fiancee and I went swimming at metro beach (it's a pretty dirty beach off lake st clair in southeast michigan). Now he has red patches on his penis (he was fine before we went to the beach) they don't itch or burn but we have been putting monistat on it and think we caught it early. My mother who has some medical knowledge says from what we described it sounds like a male yeast infection. He is also uncircumcised but uses baby wipes to clean himself after he urinates. So basically what I'm wondering is can you get a male yeast infection from dirty water. Because I just had my pap and am STD and yeast free. He's also with me 24/7 so him cheating and it being an STD is unlikely.