Headfish and Plectognath

Headfish noun - Among the largest bony fish; pelagic fish having an oval compressed body with high dorsal and anal fins and caudal fin reduced to a rudder-like lobe; worldwide in warm waters.

Plectognath and headfish are semantically related. In some cases you can use "Plectognath" instead a noun "Headfish".

Plectognath noun - Tropical marine fishes having the teeth fused into a beak and thick skin covered with bony plates or spines.

Headfish and plectognath are semantically related. Sometimes you can replace term "Headfish" with "Plectognath", this nouns are similar.