goldfish injury? fungus infection?

Question
Hello I have a goldfish named tiger,I've had him less than a year and he has been a good boy but I noticed about a month ago he had scraped against something or got in a fight with my other fish,it wasn't a bad injury ,in fact he healed up in about a week. But that was like a few months ago. Yesturday when coming back from college I saw what looked like literally cotton balls on both his sides and I also found out they are not fungus or anything but his actual flesh ,they are white and look fluffy.he has lost a lot of his colors and spots,and i do believe he will die soon. But until then what I did was put him in a baggy ,just in case if what ever tiger has is contagious. The weird part is all my other fish are just fine,healthy,fat,happy,your normal fish,except tiger.please help me figure out what this is!I've looked up lots of dieseases and illnesses that fish can get and nothing turned up.thank you so much!

Answer
Hello Nadja!

Well a diease could not have caused this because bacteria cannot rip up your fish that badly according to how you described it. Don't put him in a baggy, especially plastic ones because plastic is made of many refined oils and chemicals. As long as the bag is in the water, particles of the plastic bag may slowly erode and mix in to the tank water. Try gently putting him in a quarantine tank so no one can disturb him. Buy the API Stress Coat and observe for results. Stress Coat has the healing ability of Aloe Vera which will be very helpful in this situation. Not only that, but it also can remove stress up to 40% (scientifically proven). I trust this product 100% because it has saved the lives of many of my fish.

Feel free to ask more questions and pls give me a good rating! :D
Hope this helps!
~Sam