In article s.com,
"Karl Townsend" wrote:

Be careful, dangerous stuff electric fishing. "100–600 V (pulsed DC
selectable in 100 V steps)"
http://www.niwa.cri.nz/rc/instrumentsystems/efish

I'm not even going to ask their price. I can see its too expensive. Anybody
know how to make one of these?

The classic fish shocker was a hand-cranked telephone ring generator.
Puts out ~100 volts at ~20Hz when cranked. They were a very common
military surplus item, having been used for field phones. I recall
seeing one advertised in the last year, although I was not looking.

Joe Gwinn