There are tons of parasites the aquarium fish can catch. Some of them are fatal, some of them are just annoying. The number one killer parasite for aquarium fish is ich or ick, more commonly known as the "white spot disease". They look like white dots on fish when you actually see the symptoms. It is highly contagious. All it takes is a single infected fish to get the whole tank of fish killed if nothing is done.
My first batch of live fish was ordered online. After just a few days multiple of them showed up white spot symptoms. At the time I was just a newbie, so I gave them medications. 2/3 of the fish died during the treatment before ich was eventually eradicated.
Now I know better. There is a better, safer way to treat ich without using any medication. It is called "the heat treatment". Ich dislike warm water and will stop reproducing at over 86F. For details, we have an article on Ich Treatment Without Medication.
There are other common parasites such as gill fluke, velvet, and even some worms. Everything has a treatment or two. We will be adding more articles in our database for these cures.
