My Yellow Tang has these red blotches on him. The tank conditions are all fine. What kind of disease is this? Can the other guys catch it? He is eating, and he isn't rubbing himself on the rocks.
This is most likely a bacterial infection. I would suggest doing a large water change with aged, well areated water.
What diet are you offering this fish, how big is your tank, what other fish do you have in the tank, what are your nitrates?
The Nitrates are 0 ppm....I have Humu and Clown Triggers, a snowflake moray, and a porcupine puffer. I feed them algae strips and brine flakes in the morning, silversides and krill at nite. I do have an outbreak of green mossy algae im fighting right now that is making my tank look gross.
This question gets asked alot. I asked once and was told that when something is off in the water like PH the red blotches will be an early warning sign.They called it lateral line disease. I was advised to make a large water change and to feed food soaked in vitamins. I used Boyd's Vita-chem because it was cheaper and claimed to treat LL. This is what worked for me. Good luck