Fungus/bacterial infection?

[Ryangorami]

Hello- I am fairly new to fishkeeping. I understand maybe I am overfeeding and this problem will be rectified- but the other day I noticed a lot of white cotton fuzz on the uneaten food in the tank. Along with this, the same type of thing is on my tiger barb (attached pic). It is too small for me to see if it is "fuzzy".
I was told on reddit it was bacterial and to treat it as such, but reading into the medication I am confused. I dont know the name of the infection and so finding the "right" medicine is hard.
What do I use? How bad is this infection?
-ryan
Ps
I apologize for bad photo quality the guy is very active but doesn't have that much of an appetite as of yesterday

 

[Sokamix]

I think it is a bacterial infection. But it is kind of hard to say. I would buy tetra Lifeguard all in one. It treats everything. Cut back on the food because it could cause ammonia and nitrite spikes that can kill your fish. Hope your fish gets better!

 

[Ryangorami]

I think it is a bacterial infection. But it is kind of hard to say. I would buy tetra Lifeguard all in one. It treats everything. Cut back on the food because it could cause ammonia and nitrite spikes that can kill your fish. Hope your fish gets better!

Thank you i just ordered some.