More than 1,000 fish of various species were reported dead in the canal behind a community swimming pool in Pine Grove on Tuesday night.
Environmental Protection Department spokesman Mark Carmon says the fish kill is still under investigation.
But Carmon says biologists measured water temperatures of 80 degrees or more in the canal. And he says dissolved oxygen levels were lower than 1½ milligrams per liter of water. He says that level should be about 5.
Officials in boats were removing some of the dead fish from the canal on Wednesday.