Sardines are an excellent source of omega-3 fatty acids.  One serving of sardines will give you your recommended calcium intake. A can of sardines packed in oil has around 177 calories, 0% carbs, and 49% protein.

2 (3.75 oz.) cans sardines, packed in oil, drained, 2 tablespoons feta cheese, crumbled, 2 Persian cucumbers, chopped, 1/4 pound yellow and red grape tomatoes, cut in quarters, 1/2 cup red onions, cut in thin circular slices, 1 tablespoon capers, drained and rinsed, 1 teaspoon grated lemon zest.  Toss everything together, except the sardines.  Lightly drizzle with grapeseed oil, salt, and pepper to taste,  Scoop salad out and plate top with a couple sardines.