The dolphinarium is closed until further notice and the dolphin show Hope is cancelled for the weekend.
They are being observed and monitored and can also be treated preventively if needed, says the zoo's information officer Cecilia Björling to NT.
It was on Tuesday that the dolphin Pärla unexpectedly and suddenly died. A post-mortem examination has been conducted by the National Veterinary Institute in Uppsala, but no cause of death has yet been determined.
A dolphin in captivity can live up to 40 years old if they are healthy, according to NT. Pärla, who was born in the park, would have turned 13 this year.
If age plays a role in this, we don't know at all today, says Cecilia Björling to the newspaper.
