The grunts, surgeonfish and snapper that hang around the “Pyramid” artificial reef about 30 feet deep off the Dania Beach Pier probably are accustomed to scuba divers swimming in their midst. But on Saturday, those reef denizens probably got a bit of a shock — and an unexpected brunch— courtesy of the South Florida Divers scuba club.

Celebrating a 25-year club tradition, 14 members gathered to deploy a Christmas tree underwater and decorate it with edible treats.

Diving from the Fort Lauderdale-based charterboat Sea Experience, club president Jeff Raffa and longtime member Joe Smariga placed the seven-foot spruce — weighted with an 80-pound concrete base — on the sandy bottom surrounded by lime rock boulders and tetrahedron reef modules. To make the tree neutrally buoyant so they could position it properly, they attached two 200-pound lift bags to the trunk.

Once the tree was in place, the rest of the club members — dressed in Santa caps, reindeer horns, and other holiday-themed togs over their wetsuits — joined Smariga and Raffa and strung the tree with garlands of shrimp, scallops and milk bones. Then they all took turns posing for underwater photos and video with their handiwork.

“This was real easy,” Smariga said. “No current to speak of. A piece of cake.”

Which was about how the fish treated their new home decor. As soon as the divers backed off, a school of grunts rushed the tree, snapping off pieces of the garland, gobbling and fighting over the scraps. Holiday door-buster shoppers had nothing on them.

The tree will deteriorate during the next few weeks, and the stand will become an addition to the Pyramid.