Flathead catfish and Siluriform fish

Flathead catfish noun - Large catfish of central United States having a flattened head and projecting jaw.

Siluriform fish and flathead catfish are semantically related. In some cases you can use "Siluriform fish" instead a noun phrase "Flathead catfish".

Siluriform fish noun - Any of numerous mostly freshwater bottom-living fishes of Eurasia and North America with barbels like whiskers around the mouth.

Flathead catfish and siluriform fish are semantically related. Sometimes you can replace phrase "Flathead catfish" with "Siluriform fish", this phrases are similar.