Only was able to take a quick, poor quality photo. Reminds me of a banggai cardinalfish but with a much different pattern.
Drone footage of a Tiger Shark, near Ponta da Fragata, Sal, Cape Verde.
The footage itself is not great but, based on the video "Know your sharks from the air - identification tool for drone pilots", by NSW Department of Primary Industries | Fisheries (https://www.youtube.com/watch?v=nxh2Pp5gq3k&t=114s), it looks to me like a Tiger shark due to the long and narrow tail, rounded head, small very curved pectoral fins, etc.
Video provided to me by Oteniel Jorge Monteiro.
The time is one hour ahead of what it says.
Possibly a costal rib from a sea turtle carapace.
Fang Ming Wreck