I have a full video of it too. Recognized the tail spot.
It had distinctly emerald green fins; its dorsal one running down its whole back, as well as two separate sets of pectoral fins. It also had a large pelvic/anal fin running from the second set of pectorals to its tail. You can also see it has a large black dot in the base of its tail fin.
Captured during RIN survey on the Holland River east.
This was a bizarre sighting as we were canoeing in Georgian Bay near the town of Killarney. This “cloud” of what looked like “black minnows” was about a metre long, a half a meter wide, and about 20cms deep, moving slowly along about 4 meters from shore, and didn’t even flinch as our canoe passed over them. It appeared that many on the top of the “school?” were breaking the surface for air. Very creepy (I know - highly scientific word) 🤔