The aquarium's 90,000-gallon Caribbean Reef exhibit got a good cleaning.
Helping to scrub down the state of the art tropical habitat was Illinois Treasurer Dan Rutherford, who donned scuba gear for the job, cleaning away as sharks, stingrays and other tropical wonders swam around him.
Rutherford's work was part of Shedd's Earth Day Picnic for the Planet celebration.
"Recognizing that the Shedd is such an advocate for conservation, I am proud and honored to participate in the Earth Day," he said.
It included a tent picnic on the lawn, part of a world-wide attempt at a Guinness record for most picnics taking place in a single day.