“I know you, codfish, even you come in costume.”

It means you can't fool someone who already knows you well.

Translation in spanish

“Te conozco bacalao, aunque vengas disfrazado.”

Significa que no puedes engañar a alguien que ya te conoce bien.

Phonetic:
/Teh koh-nohs-koh bah-kah-lah-oh, ah-oon-keh ven-gahs dees-frah-sah-doh/