When I first added my two goldfish to my 29 gallon tank, the ryukin got one big red spot or injury on his side and a smaller one on the other side. After doing some researchand in spite of my parameters being almost perfect, I decided that it was a water quality issue. The only problem was a slightly low alkalinity. I was already doing one 30% water change a week, including vacuuming the gravel. So, I increased it to two. He got better for about a week and was looking beautiful again, I hadn't realized just how bad he looked until he got better. Now the red spot is back, not as bad as before though, and he has some sort of a raised lump on his side. The only way I can think to describe it is scar tissue. Can fish get scar tissue? Is there something more serious wrong with him? I have added some aquarium salt and melafix to the tank. I'm still doing two 30% changes a week. What is going on? Any help or insight is appreciated.