I noticed that my two comets have developed black lines between their eyes and gill slits. I noticed it on one side on one comet a couple days ago. I figured I would watch it and see what happened as I know fish can change color. Maybe he was developing black pattern marks. Today, I noticed that it now has it on both sides and the other comet has it on one side. The Sarassa shows no sign of it yet. My water is crystal clear, parameters normal except PH is 8.2 and water is hard. (comes like that from the well) I have had a little string algae, but not enough to even bother with. I tried to take pictures but the batteries are dead in my camera. I put them on the charger, but won't have them available until tomorrow. The fish are active as usual. No noticed flashing. Eating ravenously. (As is the Sarassa) Not gasping at the surface for air. I have a waterfall and a spitter for aeration. Water level is down a few inches in the past couple days due to a small leak in filter line. (Haven't been able to fix it as I have been under the weather my self.) Last water change was about 4-5 days ago. No more than 10%. I have done some research, the nearest I see would be black spot, except these are not spots but lines about 3/8 of an inch long and 1/16of an inch wide. Kinda comma shaped, parallel to the gill slits.