Betta Fish with Cold Sores?

Lymphocystis is a virus that can infect all fish. One a betta or any other fish has become infected you will start to see signs of it either on the body or fins. The infected area starts out with a small growth that gets bigger as it fills with fluid. At the end of four weeks the sore pops releasing the viral fluid into the surrounding water. This is much like cold sores or herpes especially because there is no cure. It is a reoccurring and communicable infection that can only be somewhat controlled.

Luckily it is a very rare virus that can be easily prevented. Get the full scoop here: Betta Lymphocystis