Gudgeon and Minnow

Gudgeon noun - 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.

Minnow and gudgeon are semantically related. In some cases you can use "Minnow" instead a noun "Gudgeon".

Minnow noun - Very small European freshwater fish common in gravelly streams.

Gudgeon and minnow are semantically related. You can use "Gudgeon" instead a noun "Minnow".