[LittleBlueFishlets]

Does the fuzz look like this?

If so, it could be Columnaris, which is a common bacterial infection. Or it might be Saprolegnia, which is a fungal infection. (Both diseases result in white fuzziness.)

Here is an excellent article describing the differences between these, and how to treat them: http://www.americanaquariumproducts.com/columnaris.html

 

[LittleBlueFishlets]

I see that you've lowered the water temp to the mid 70s, which is good.

(Edited to remove additional information about treatment. I want to check some things before posting.)

 

[LittleBlueFishlets]

Keep us updated!