Dont worry man, its alot of hit or miss when your new. being that ive already explained bacterial infections in a number of post tonight and im getting tired, ill make this brief.
It does look like mouth fungus, which is really a misleading name for a type of very hard to kill gram - bacteria that is very common and attacks weak fish...its usually 100% fatal but you have caught it early which means their still hope.
I highly reccomend a hospital tank like a cheap ten gallon or a tub.
You have some choices.
"Terramycin"---Oxytetracycline
"Kanaplex"-----Kanamycin
"Maracyn2"----Minocycline
The fungus is secondary to areas where the bacteria has eaten at the flesh of the fish, so you must kill the fungus as well.
here we go again with the long post, the list is like this
Kanamycin combines with Furan 2
Oxytetracycline Combines with Methyl blue
Not sure what the minocycline you combine with, maybe primafix would work.
Give this a read, remember that your dealing with F. Columnaris, gram-negative
Also note that the tetracycline class drugs are not very effective in hard water or high PH calcium type water, that most of us have in the US.
You can get around this by using medicated feed like this
Ken's Premium Sinking Pellets with Oxytetracycline 2.5mm
Or this is a good place to get ALOT of medicated feeds as flake form
Antibiotic Fish Flake Food
Powder Kanamycin is fine in hard water but dont overdose and at 15 dollars a small bottle, use in hospital tank would be best.