The red on the bottom are likely baitfish clouds. The thermocline was also around that depth out that far, but it doesn't normally show up that well defined. It is usually just a faint horizontal line. I see that you are in 200kHZ mode, which is a fairly narrow cone angle. At 2.5 mph, those vertical lines could be fish that are in and out of the cone very quickly. I normally see marks like that when I am scanning for fish at 25-30 mph. Next time you see that, try switching your mode to 83 kHZ and see how they look then. Otherwise, they could just be interference or baitfish practicing their synchronized swimming in a vertical pattern....