Synonyms for Gudgeon (same or very similar meaning)
WordNet sense 1 (small spiny-finned fish of coastal or brackish waters having a large head and elongated tapering body having the ventral fins modified as a sucker):
gobyWordNet sense 2 (small slender European freshwater fish often used as bait by anglers):
Gobio gobioFrom the ODE community, based on WordNetadd/edit