"As I was preparing tea of 3 dog fish, which had been killed, skinned and gutted.They started to freak me out !!!"I seem to remember something about dogfish (if that's what they are...) having very primitive nervous systems. I've never seen any activity remotely like this with Minnesota walleye...
Via Arbroath, where there's a second video taken an hour later -- and they're still wiggling!
Addendum: Richard Hartmann and nfm girl point out that the applicatin of acidic lemon juice (??and salt) to a freshly dead specimen placed on aluminum foil probably creates the trigger for the movement. This totally makes sense to me. Perhaps I'll try it sometime.... (with a fish)
Update: Full explanation, courtesy of "KickinPhresh" at Reddit:
The flopping action is actually the stimulation of local central pattern generators. (CPGs, yes, these are real things) A central pattern generator is a neural circuit which generates oscillatory patterns. Walking, respiration, slithering, and swimming (in the case of fish) are all driven by central pattern generators.
The general scheme of a central pattern generator is left/right and extensor/flexor antagonism. When any muscle moves, the opposing muscle will be simultaneously inhibited by an interneuron to allow for efficiency, and this motion with be 180 degrees out of phase with the contra-lateral side.
Fish have local central pattern generators up and down their side that coordinate this motion WITHOUT the brain. (Animals do too, remember what the beheaded chicken does?) The pattern is generated locally, and only modulated and switched on/off by the brain. The motion seen in the video is due to the activation of central pattern generator circuits. The motion in the video is likely due to the activation of CPG circuits by high sodium.