Which of the following is not an example of an amphibian ?

Seahorse is the name given to 54 species of small marine fishes in the genus Hippocampus. It comes under Animalia kingdom; Chordata phylum; Actinopterygii class. Having a head and neck suggestive of a horse, seahorses also feature segmented bony armour, an upright posture and a curled prehensile tail.