Betta w/raised scales in one spot

Question
Hello,

My question is similar to:
http://en.allexperts.com/q/Fish-1472/2009/3/raised-scales-bettas-gills-2.htm
I didn't see a clear answer on that and I don't know what happened to that person's fish but my betta has the same problem. I didn't notice it yesterday so I am assuming that it just happened last night or today.  

My betta is in a 12 gallon Eclipse tank with 2 albino corydora and 1 spotted corydora.  I just noticed that he has a raised area on one side of his body with raised scales just in that particular spot. The skin underneath the raised scales looks red. The water parameters are ideal : no ammonia, around 78 degrees. I can't add much aquarium salt because the corydora are very salt sensitive. They have been living together for a long time with no problem so I don't think they attacked him. Do you think this is dropsy? He's not been overfed and I saw poop so I don't think he's constipated. He's eating and being active. I'm worried it's the beginning stages of dropsy.

I managed to get a picture of the raised spot:
http://i43.tinypic.com/14ca8tt.jpg

I hope the picture helps. Thanks in advance.

Answer
Hi Teera,
Raised scales usually indicate Dropsy.  Dropsy it seems, is impossible to cure.  Researchers cannot agree on what exactly causes this disease.  It is very infectious.  Fish usually get dropsy if they have been stressed by another disease or by bad water conditions.  It can also be caused by food that burdens the liver such as black worms.  The disease destroys the liver mucous membrane and causes ulceration.  The liver is damaged and eventually destroyed, and numerous other problems may occur.  
It could also be a tumor, which may or may not be cancerous.  Bettas live a long time with a tumor that is not cancerous.  It could also be parasites.   It could be a boil, and if it is, it will go away on it's own, much like us.  It will come to a head, and then go away.  Never try to squeeze it, it could kill your betta, and would be very painful.
When it comes to lumps, it is very difficult to diagnose the problem.  Only a vet can do this.
I'm sorry, I cannot help you more.  Watch him very carefully and see if this lump gets bigger in the next few days.  
Keep his water very clean.  Poor little guy, I hope it is a tumor, and nothing more.  If he is eating, this is always a good sign.  A sick Betta usually stops eating, so hopefully it is a tumor, but I cannot guarantee this.  I wish I could help you more, but it is impossible for me to do so.  A vet has the tools to see what this could be, and the medication that could help him.  Some medication, usually the good ones, cannot be found in Pet Stores, and have to be bought at the vets.
Lets hope he gets better.
Lynda