01 July 2010

A headless, skinned, gutted fish wiggles in the kitchen

"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.


  1. I only watch about two seconds of this on Arbroath. I don't know if I can ever eat fish again. I'm pretty sure I won't ever cook a fresh fish. Ghastly!

  2. Muscles are excited/contracted using electric impulses through the nervous system.

    The fish are on aluminium foil and there are several pieces of lemon on the foil.

    I will leave the rest of this as an exercise to the reader.

  3. I'm with Richard. There is a similar video on YouTube of frog legs "dancing". It is caused by the salt sprinkled on them, which makes sense to me.

  4. Post updated (and category changed from WTF to science and nature video). Thank you!

  5. Sorry, but this was hilarious!!! Zombie Fish!!!

    Reminds me of chickens with their heads just cut off.

  6. Growing up on a lake in Minnesota, we used to catch one or two of these per summer. Usually quite large (8-10 lbs), dogfish were considered invasive to other species in the lake. They were also considered pretty repulsive to clean and eat.

    So we used to just throw them up on the beach and chop on them with a shovel to kill them. But the weird thing about it was...they were like zombies. No matter how dead we thought they were or how far off the beach, they always managed to wriggle their way back into the water! The next day, the fish would be gone and there'd be a trail in the sand where it wriggled back into the water!

    We finally took to burying the darn things 50 yards or so from the water.

  7. The thing that struck me is that the cells are still alive and able to function, even after everything that happened, and the time that passed. Kind of makes one rethink 'death.'


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