Yu Pyong Guk, a researcher of the zoo, told KCNA over a hundred sea fishes of some twenty kinds were living in the aquarium with recycled seawater.

It is widely known that seawater can be used in aquarium and saltwater fish farm for only three months.

They electrolyze already used seawater to make it nonpoisonous and filter it for a week with reduced stones calcinated in high temperature to make all quality indicators normal.

Fish can live in the recycled seawater for nearly a year.

This seawater recycling method is also available for saltwater fish spawning ponds and farms.