In a shallow bowl, combine the scallops, avocados, radishes, shallots, mango, serrano, lime juice and zest, grapefruit juice, lemon juice and zest, agave and 2 teaspoons each salt and pepper. Gently mix with a rubber spatula. Cover and chill for 1 to 2 hours before serving. Serve cold.
This recipe was created by a contestant during a cooking competition. It has not been tested for home use.