Hey, I have an average size Head and Tail Light Tetra who all of a sudden started to breathe heavily and not eat. The tank has very low ammonia and nitrite levels and also has decent oxygen levels. I did notice he had black/gray areas on him from a couple months back when there was an ammonia spike but he never lost the spots and never stopped breathing heavy after quite some time. There looks like there are a few pieces of this white stuff on him, 1 piece on each side and one on the top fin, it isn't ich. I'm wondering if it is a bacterial infection or something but I don't know what to do. How should I treat it?