I am from the Bahamas and the way we keep fresh fish from falling apart is this:
After seasoning the fish, take a clean hand towel and gently tap the water off the fish until it's damp but not dry and be careful not to rub off the seasoning. Take a flat plate, sprinkle some flour on it and spread the flour to ensure it coats the entire plate. Take the damp fish by the tail and dip both sides of the fish in the plate of flour. Make sure the fish is lightly coated from head to tail.
Use a skillet filled with approximately 1/2 cup of oil and fry the coated fish on medium heat.
When you notice the fish is slightly brown, turn the heat up and fry to a crisp golden brown. Add oil only as needed, too much oil will soften the fish and too little will cause it to stick. Watch the pot carefully and use a spatula to flip the fish. When flipping, make sure the spatula is in between the head and the body section.
This method is done before we cook the fish in any other form to prevent it falling apart. This is especially done before the fish is steamed, because it decreases the cooking time of the fish sitting in gravy, which causes it to fall apart if cooked for a long period of time.