The phrase "odd fish" refers to someone who is unusual or eccentric. There are many synonyms for this phrase that can convey a similar meaning. Some of these synonyms include "weirdo," "freak," "misfit," "oddball," "eccentric," "quirky," "unconventional," "offbeat," "strange," and "peculiar." Each of these words has a slightly different connotation and can be used to describe someone who is different in their own unique way. Whether you are looking for a more lighthearted term like "quirky" or a more negative descriptor like "freak," there are many ways to describe someone who stands out from the crowd.