It does seem like a fungus from what I can see. One of my mollies has a similar condition, currently I am treating with Maracyn. But as I have been advised be careful and test your parameters often as it can affect the bacterial colonies. Maracyn and maracyn II are fine with cory's btw
. I also recently found out that it is better to keep the temps down around 76-78, I had originally raised my temp as you would with ich.