For the batter, combine all ingredients and mix until smooth. Chill.
Fillet the pike, cutting out bones with a sharp, thin fillet knife and plucking out cross bones with tweezers if necessary. Cut into small fillets. Season with salt, pepper and lemon juice.
Heat plenty of fat in a frying pan. Turn fillets in flour on both sides, pull through batter and fry in hot fat until golden brown and crisp.
Remove and drain well on kitchen paper.