this morning I noticed one of my oscars acting a little strange he is sitting at the bottom a lot, ocassionally he will swim up to the top espically when I approach the tank but soon falls to the bottom and sits there. I tested water and everything in normal but the nitrates were a little high im going to do a water change after work today and do one a day until I see signs of recovery. I did make the stupid mistake of leaving my night lights on last night which is a dim blue light not sure if that could be messing him up. any help would be great thanks