The U.S. Supreme Court is once again deciding to stay out of the fight over invasive Asian carp.

The high court on Monday shot down an appeal from Michigan and four other Great Lakes states. The states are suing the Army Corps of Engineers and the City of Chicago.

The states had wanted the court to order that fish nets be laid out to prevent Asian carp from swimming into Lake Michigan. They also wanted an order saying the Army Corps of Engineers has to hurry up with a plan to isolate carp-infested waterways.

John Sellek, with the Michigan Attorney General’s office, said Monday’s denial from the justices is disappointing.

“Asian carp are, essentially, right at downtown Chicago,” Sellek said. “They are lurking about and about to go into the Great Lakes. And that’s something that would be detriment to - not just the other states, but to Illinois, as well.”

Sellek says Michigan will now try other legal methods meant to prevent the hungry fish from devouring the Great Lakes ecosystem.

The Army Corps and the state of Illinois have maintained the threat posed by carp is not as drastic as the other states would argue.

Monday’s ruling marks the third time Supreme Court justices have opted to stay out of the fight over the spread of Asian carp. The high court had earlier denied emergency requests to close down some Chicago-area waterways that link Lake Michigan to the Mississippi River.