Finish the tail area with 11.25 Remora use their suction-cup-like dorsal fin to hitchhike on larger sea creatures like rays, sharks, and whales.
Lampreys are fish with primitive features. Together with hagfish, they are the last surviving jawless vertebrate. These creatures don't exist in my home country, so I've only known their existence from encyclopedia back in elementary school. Their somewhat scary circular mouth is full of teeth and will surely etch into memory.