The term "gudgeon" refers to a small freshwater fish belonging to the family Cyprinidae. These fish are commonly found in rivers and ponds across Europe and Asia. Gudgeons typically have elongated bodies and can grow up to 15 centimeters in length. They are known for their distinctive barbels on the lower jaw, which help them forage for food on the riverbed. Gudgeons are often used as bait for larger fish due to their abundance and size. They primarily feed on small invertebrates and detritus, playing a vital role in the aquatic ecosystem. Their presence can indicate the health of freshwater habitats.