Crush the coriander seeds, fennel seeds and garlic cloves in a pestle and mortar then empty into a bowl.
Mix in the flour, turmeric, chilli powder, garam masala and salt.
Place the fish fillets into the masala mix and coated them then set to one side.
In a large deep frying pan, add enough vegetable oil so it's about 5cm deep to fry the fish.
Gently heat the oil and test whether it’s ready by dropping a small bit of the masala mixture into the oil, if it fizzes and turns brown in a few seconds the oil is ready.
Very gently slip in a couple of fish fillets and cook for around 4–5 minutes, gently turning them over until cooked through and they have turned a wonderful yellow colour.
Drain on some kitchen paper.