Sick Tiger Barb?

Question
I have a 20 gallon tank that I've had set up for close to two years. I have six tiger barbs and five neon tetras in the tank. For a while now one of my tiger barb's and one of my tetras have been bloating. The tiger barb is losing scales in the area of the bloat. I am worried it is the myxobacteriosis. I frequently(every week to two weeks)partially change the water and use aquarium salt. They are still swimming with their schools and neither has lost any color or stopped eating. I have tried to no avail though to get rid of the unsightly bloating and am worried about them infecting the rest of the tank. Any help would be great! Thank you.

Answer
Elizabeth,
could be dropsy as well.
in which case there is not much you can do.
it usually has something to do with water conditions so do a quick check of PH, nitrate and also, take out some water in a clear glass and put it side by side with a glass of water from the tap.
That will give you a general idea of the condition as old water gets a yellowish tint to it.
In which case water changes, 3gals at a time would be in order.
Keep the temp up a bit to 80 and let me know what happens.