Do you think its ammonia burns by looking at my display picture
As a general rule of thumb, fish diseases are the result of improper husbandry issues eg not cleaning the tank often enough, introducing new fish without quarantine etc. Most fish diseases are better prevented and this can be done by ensuring good husbandry practices and that water quality is in tip top shape. The problem with fish disease is that because it is usually a consequence of poor husbandry, it is not often easy to establish that there is just one type of problem going on eg it's only a fungal infection, or purely a bacterial problem. A lot of the times it's a combination of the lot and one just seems to have affected the fish more than another. Whilst the best treatment for fish disease is to come to a proper diagnosis first BEFORE embarking on treatment, more often than not, the ALL in one type treatment regime to cover your bases is utilized for convenience sake.
The first sign of fish disease is usually lethargy and loss of appetite - your fish may just lie on the bottom of the tank a lot or seem 'sleepy' - further investigation is required to get down to the bottom of what the cause is. Your first action point when you notice these first signs of fish disease is to check your water parameters (water quality).