An issue overnight is keeping Mesker Park Zoo from opening on time Monday.
Zoo officials say there was an overnight die-off of fish in the zoo’s Lake Victoria.
Crews are cleaning up the area and trying to determine what caused the fish to die.
Staff veterinarian Dr. Carrie Ullmer will be examing the fish to determine an exact cause.
One possible issue being looked at is a low concentration of dissolved oxygen in the water because of high temperatures and lack of rain.
There’s no word yet on when the zoo will open.