Lee said it appeared that a muscle in the trout’s mouth was severed in the past, causing thin membranes between the lower jaw bone and the floor of the mouth to split. He said that caused the floor of the mouth to drop.

“This gives the appearance of two jaws. It also results in the fish having no practical floor to its mouth,” Lee wrote in an e-mail.

Despite the odd condition, Lee wrote, the trout appeared to be in good health and was able to live, feed and grow to adult size. The fish came from a Nebraska fish hatchery.

Olberding, 57, caught the unusual trout at Holmes Lake in December. The trout had a normal mouth and another one below it that led nowhere. He snapped photos of the fish and then cut off the head and put both pieces in the freezer.