Pufferfish and Plectognath

Pufferfish noun - Any of numerous marine fishes whose elongated spiny body can inflate itself with water or air to form a globe; several species contain a potent nerve poison; closely related to spiny puffers.

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

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

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