Attorneys in federal court today discussed the challenges of preventing an invasive fish from making Lake Michigan its home.

Most of the testimony centered around General John Peabody. He’s with the Army Corps Of Engineers and has been trying to find ways to stop the invasive Asian carp from migrating any further north. Peabody told a federal judge he thought if the carp settled in Lake Michigan, there would be steep consequences for the region’s ecology. But he says there are practical and financial issues with keeping the carp out of the lake.

His testimony comes the same day the White House named a carp czar, who will oversee the process of fighting the Asian carp. Testimony is expected to wrap up on Friday.