Bill,
Great pict! It looks liek it could be bass schooling from the size of the shadows. In the second set of images, there may be some individual fish near the bottom but hard to say.
If you would bring your range in some you would be able to see the individual ones a little better. Rule of thumb, especially if you are scanning with 800khz, is keep the range at 2 to 3 times your depth.
Good Luck,
Robert