A fish hatchery used shock treatment to put fish into anesthetic effect sleep. Two parallel wire screens two feet apart and using 110 volt line current for 5 to 7 seconds gave a two minute stun to 88 Brook Trout for about two minutes.
Handling, weighing, or treating fish in stupor without harm and no noticeable ill effects was a plus. This has been used in portable equipment to take census of fish streams.
