advise

My parrot fish has white silvery patches on his gills and face, he seems fine and eats well, I was wondering if it was some type of scale damage or ulcer and how I would treat it? thanks

I have two Oscar's and two bristlnose plecos and was wondering what would be the best choice of large aquarium rocks the put in my tank. I have a 75 gallon tank wide I'm also going to put a diy bubble bar in the back of the tank Is it possible that I can put a natural obsidian rock structure...