I have a 6 year old bolivian ram that has started to show a white film on his scales. I know that he is quite old and I believe this is a bacteria infection due to his age. I am hesitant to put him through any type of treatment. the first thing I am concerned about is will this bacteria spread to my other fish? I read that it isn't really an opportune infection since the aquarium always will have bacteria in it. it seems to be a disease that occurs when the tank is not well taken care of or if the fish already has a problem such as mine being so old. this aquarium has been set up for 10 years. all parameters are normal and a 25% water change is done every 5 days. all other fish are healthy. my ram is eating, swimming and acting normal. I am thinking of just letting this run it's course. I don't think he would survive the treatment. just don't want other fish to get infected. any advice?