Thanks for the responses. These were definitely not plankton because we were in 13ft of water and could see the baitfish and bottom. If you noticed this was a snapshot taken from a recording and was paused after forward and reversing the play. I've since gone back and tried to duplicate the image and cannot so I'm guessing it was an anomoly in playing back the recording...something I've never noticed before. I don't think there is a way that something on 2D wouldn't show in the SI because of the coverage but those smarter than I might have an example...LOL