Really, really historical piscine pictures

Just a few months ago an expedition captured the first live video footage of a giant squid in its deep sea realm.  Now there's a video of a live oarfish in the depths of the ocean, too.  Oarfish, for those who can't wait to watch the video, are a very long narrow fish with a dorsal fin that is almost the same length as the fish.

What gets me is the pattern of movement of the dorsal fin.  It appears to have two wave functions, one moving in about the first 2/3 of the fin and the other in the rear 1/3 of the fin.  Sometimes the front part of the fin is moving in a different direction than the rear part of the fin.

Amazing era in which we live, isn't it?

Video of an oarfish in the wild