Clean the fish steaks and let the excess water drain. You can also use a Kitchen towel to mop up the excess water (check notes on why this is important)
In a bowl, mix all the ingredients to prepare the marinade.
The marinade should be a thick paste so the moisture from the shallots and ginger garlic should be enough but if not, add a few drops of water
Coat the fish pieces generously on all sides with the fish fry marinade
Let the marinated fish pieces sit in the fridge, covered, for at least 30 minutes or overnight
When ready to fry, heat enough oil to shallow fry the fish
Gently drop each fish piece into the hot oil and keep the heat medium high
Fry both sides until dark brown and the fish is cooked through (check notes for a few tips)
Serve hot with raw onions and lemon wedges