i woke up this morning to see that my two oscar fish have lines on the outside of their gills on both sides in the same place so i know it cant be from fighting. does anyone know what this could possibly be is it natural? i have one tiger and one red and the lines are both red but different shades like the tiger oscars is really bright just like he is and if im not mistaken i think i see some black spots in it and the red oscars is like a dark red like he is so im thinking their natural but they are new so i wanted to make sure. thanks in advance