Tetraodontiformes are an order of ray-finned fish, also called the Plectognathi. Sometimes these are classified as a suborder of the Perciformes. Various bizarre forms are included here:
- Balistidae (triggerfishes)
- Monacanthidae (filefishes)
- Ostraciidae (boxfishes)
- Tetraodontidae (pufferfishes)
- Diodontidae (porcupinefishes)
- Molidae (marine sunfish)