In Dnipro, residents noticed that pieces of cut fish on the counter were moving while shopping at a supermarket, as reported by "Vydomo" referencing the Telegram channel Trukha Dnipro.
This surprised onlookers, but it merely indicates that the fish is fresh. This is a detail of fish anatomy and not an uncommon occurrence for even fish fillets to "jump."
The fact is that, despite the brain and heart of the fish no longer functioning, its cells still respond to stimuli, particularly to salt. Therefore, a dead fish will continue to move until it depletes all its energy reserves. However, this does not mean that the fish is alive or feels pain.