Based the on the description of the sore at the base of the fin, I'd say you have a bacterial infection. However, to clarify, that would be considered an external infection. Treat the tank (if you can isolate the sick fish in a small tank, that's best) with a wide-spectrum antibiotic. I've had great success with erythromycin (at 2x or even 3x the recommended dose in bad cases). Some of the furan-type antibiotics may also do the trick. Additionally you can use acraflavin drugs, they work well.
The white ball on the fin can be parasitic, bacterial or viral. Without seeing it I can't say for sure. If it's viral (lymphocystis) then there's not much you can do as there's no cure. It will come and go as the fish ages. Sometimes it vanishes forever, sometimes it gets so bad the fish dies. If it's a parasite, try one of the several formalin based remedies, they do a good job.
If in doubt, treat for parasitic and bacterial issues at the same time. Most medication producers will clearly state on the labels if the meds can be used in conjunction with other meds. Read the labels for the active ingredients, that'll help you choose alternate brand medications to use together if you can't get different meds in the same brand.
This is all my opinion and based on my own experiences. There may be other, more experienced aquarists here with more years keeping fish than I have who will offer better recommendations.
Hopfully somebody can answer this query for me , i noticed yesterday that my Golden Gourami has 1 white raised spot on his pectral fin. The other part to it is that the fish has a very sore base to the pectral. I have looked in the A to Z of desease and the closest thing that it sounds like is a lice that has attached itself. Basically i'm asking anybody out there if they have any other idea to what it could be besides this, before i start treatment. The fish is still active and feeding well and shows no sign of distress at all. I recently have added to the tank more plants and i was wondering weither the lice had came into my tank from one of these. Have no idea were the problem came from. All water parameters are correct and i do frequent water changes every 4 days, any info would be gratefully recieved.
/www.fishdoc.co.uk/disease/argulus.htm
And big, there's no mistaking them.
