1.Score squid in a diagonal pattern. Cut squid and fish into 3cm pieces; shell and devein prawns, leaving tails intact. Remove and discard head and beak of each octopus; cut each octopus in half. Rinse under cold water; drain.
2.Heat half of the oil in wok; stir-fry seafood, in batches, until prawns are changed in colour, fish is cooked as desired, and squid and octopus are tender. Cover to keep warm.
3.Heat remaining oil in wok; stir-fry garlic, chilli and carrot until carrot is just tender. Add capsicum; stir-fry until capsicum is just tender. Return seafood to wok with onion, sauces and juice; stir-fry until hot.
4.Heat extra oil in small frying pan until sizzling; fry basil leaves, in batches, until crisp but still green. Drain on absorbent paper. Top seafood with basil leaves.