Hundreds of dead fish were found floating in a pond at the National Mall in Washington D.C., prompting officials to test the water and algae levels in the pond.
The National Park Service is cleaning up the carcasses on August 15 while the D.C> Department of the Environment took water samples for testing, reported WJLA.
The likely cause is an algae bloom that sucks oxygen out of the water.
Officials say it could take several days to determine the cause of death.