stabbing a fish in the brain for a quick kill.

in general, the brain is in the same spot for most fish?

I watched a Japanese fisherman simply jab his knife into the side of a fishes head, way further back than I would have imagined the brain to be, and kill the thing so quickly!!

I'm not buying a spike or anything,but I always have a knife on my belt, and hope to use that.  he came at it from the side.  then he cut the gills. 

what do you all do?

As I understand it from I think an Outdoor Chef Life video, the brain is always in-line with the eye.  So line up your blade on top of the skull with the eye, and push in and I give it a turn.  However for trout I find it easier to just whack them on a the side of my kayak in about the same location 

I usually just use a knife too. I just give it a good stab, and of I see the fish tense up, I know I found the right spot. Sometimes it takes a stab or two for me to find it.

I usually cut the gills first though.

After cutting my finger with a knife on the water, I seldomly use a knife on the yak. I use ice picks for brain spiking and they work very well and they are cheap. 2 pack for $10.

After cutting my finger with a knife on the water, I seldomly use a knife on the yak. I use ice picks for brain spiking and they work very well and they are cheap. 2 pack for $10.

This is a good idea, I'm kinda clumsy and probably lucky I haven't stabbed/sliced myself yet, haha.

With halibut I'm always 2nd, 3rd guessing and just jab it all around the eye area multiple times like a psycho killer.  They still seem to throw out a surprise burst of energy, even a half hour later, so it's hard to know.

After cutting my finger with a knife on the water, I seldomly use a knife on the yak. I use ice picks for brain spiking and they work very well and they are cheap. 2 pack for $10.

Agreed. Cheap spikes work great. No need to spend more.

With halibut I'm always 2nd, 3rd guessing and just jab it all around the eye area multiple times like a psycho killer.  They still seem to throw out a surprise burst of energy, even a half hour later, so it's hard to know.

Seconding this. The “between the eyes” works great on all fish except flatfish.😂