Everybody has fungi on their toes and fingers which are living organisms that live on our bodies with various kinds of other bacteria. These living fungal organisms usually do not generate any condition but fungus is very opportunistic. The fungus flourishes in warm, humid conditions like the inside of your shoes and under your socks. If you have infected toenails this will most likely cause discolored nails. This has nothing to do with your hygiene, you can wash your feet multiple times a day, and still get the fungus. So, here’s how you might have got the fungus to infect the nail. If you have damaged your toenail such as someone stepping on it, you stubbing it, or dropping something on it. Then, that opportunistic fungi steps in and finds a path beneath the nail. And, because the fungus is down in the nail it can become shielded by the nail itself, which then allows it to lie dormant for any amount of time. As this happens it may start to infect the neighboring nails and you may not be able to notice for months after the damage.