Stir the halibut, shrimp, scallops, lemon juice, and grapefruit juice together in a glass bowl. Cover, and refrigerate at least 6 hours until the halibut turns opaque.

Stir the bell pepper, jalapeno pepper, onion, olives, ginger, sugar, salt, and tomato paste together in a glass bowl until no chunks of tomato paste remain. Drain the seafood, and add to the vegetable mixture along with the tomatoes. Gently stir until evenly combined, then return to the refrigerator to chill at least 15 minutes before serving.