How is the paraguard? I'd never try a medication that doesn't disclose its ingredients. There is a big difference between bacteria and fungal issues. Malachite Green for example is too toxic and would be bad to use here.
The suggestion of topical application directly on the infection site is excellent advice. Use undiluted out of water on the affected area so less disruption of bio filtration, less poison (medication) and less cost. Usually acriflavine (most anti fungal medication) is good, hold fish tail down so gravity runs away from gills. In this situation, so close to gills, I would use betadine gel ointment/cream instead- (not the liquid) which is 10% povidine Iodine and suitable for bacterial, viral and fungal infections. Dab long enough to deeply stain the fungal hyphae.
Would not use a confining net as this would stress the fish too much. 10 gallon tank is easy to catch out. Keep tank dark - no feed - etc etc. I'm sure you have treated sick fish before.