Possible Dwarf Gourami Disease

Question
I currently have a 20 gallon tank with 5 gourami's (2 blue and 3 with red stripes) 6 tetras (don't remember what kind but they are small and red/orange)2 algae eaters (not plecos but some other kind that only get about 4 inches)an albino rainbow shark and 3 panda corys.  To get to the point, I noticed that on one of my red stripe gouramis a couple of days ago that he seems to have a weird blister like thing on the right corner of his mouth.  He seems to act normal and eats like the rest of them.  Is this a disease that it may have?  Will it affect the other fish in the tank?  It does seem to have a little blood in it but I know that it definitely is not normal as the others do not have the same thing.  Please advise.

Answer
Hello Michelle-

Sorry to hear about your little guy!

There are two main things that could be the cause of this wound - bacteria, or your other gouramis.

Gouramis can get aggressive with one another, and the open sore may be a battle wound. If you see this one actively getting picked on, you may want to remove him (or the bully) for the fish's well-being.

In any case, I would advise adding a dosage of aquarium salt to your tank, and treating with Melafix. It would also be wise to start using a broad-spectrum antibacterial medicine, if you can find a small dosage at your pet store. This will kill off any bugs in the tank and prevent (or clear up) any infections.

Hope this is helpful, and good luck!
-Amber Worman