For your stock, simmer shrimp shells (feel free to add carrot peels, celery leaves, fennel greens, and onion skins) in 1 gallon water for 2 hours. Strain and reserve stock.
In a large stockpot, add carrots, onions, celery, fennel, and okra, and cook on medium-low heat until onions are translucent, about 5 minutes.
Add shrimp stock, garlic, tomato puree, bay leaf, thyme, chipotle, and oregano. Simmer for 2 hours.
Add scallops, white fish, Pritikin Fish Seasoning, and red pepper flakes, and simmer for 1 hour more, breaking fish with back of spoon.
In last 5 to 10 minutes of cooking, add shrimp, clams, and black pepper. Simmer till shrimp and clams are cooked. Remove chipotle and bay leaf. Garnish with cilantro. Serve.