Seafood girl from a popular variety show, a man said a sentence: I introduce you to the fresh girl, not seafood girl. And then it exploded on the internet. There is a fresh girl to do the comparison, but also roughly guessed seafood girl is probably what it means. Fresh stands for clean, while seafood is aquatic products with flavor.
Seafood girl should be a flirtatious remark. Seafood more or less has a fishy odor and is still dirty before it is cleaned. The stanza is supposed to mean that the girl is unclean, dirty and smells bad. Or that the girl is a bit promiscuous and doesn't pay attention to personal hygiene. I guess men prefer fresh girls to seafood girls.