It was free pedicure as we rubbed the soles of our feet on the stone steps and dangled _______ in the water for the fish to nibble away _________ the dirt.
feet are being talked about as initially mentioned in the sentence, and repetition of the noun isn’t correct grammar and thus pronoun referring to the feet ‘them’ will be used. For the second blank, one nibbles ‘at’ food. It was free pedicure as we rubbed the soles of our feet on the stone steps and dangled them in the water for the fish to nibble away at the dirt.
