Why is a trigger fish called fish?

Triggerfish are called "fish" because, simply put, they are fish. They belong to the Balistidae family, which is a group of fish characterized by their distinctive trigger-like mechanism on their dorsal fins.

Just like a shark is a fish, a tuna is a fish, and a goldfish is a fish, a triggerfish is also a fish. The word "fish" is a general term used for aquatic vertebrates that breathe through gills and have fins for movement.

So, while triggerfish have unique features that give them their name, they are still part of the larger category of "fish."