Cut cod into medium size chunks. Cover cod in water. Soak in refrigerator, changing the water 2 to 3 times, every 6 to 8 hours for about one day. In skillet, saute onion until softened, add tomato, peppers, thyme and cod. Saute for 5 minutes and add black pepper to taste. Add ackee and stir gently to combine, simmer until just warmed. Add scallions and salt and pepper, to taste.
PLEASE NOTE: Eating unripe fresh ackee is unsafe. Only ripened canned ackee is available in the United States. It is regulated and certified by the U.S. government to be ripened fruit and safe for consumption.