Alex Mustard / Hedgehog seahorse (Hippocampus spinosissimus) female moves over a sandy seabed. Dauin, Negros Island, Philippines. Bohol Sea, tropical west Pacific Ocean.

Alex Mustard / In-camera motion blur image of a female Hedgehog Seahorse (Hippocampus spinosissimus). Lembeh Strait, Sulawesi, Indonesia, Molluca Sea, March.

David Fleetham / Giant porcupinefish (Diodon hystrix) at night. Kauai, Hawaii.

Richard Robinson / Spot-fin porcupinefish (Diodon hystrix) at North Minerva Reef / Teleki Tokelau a disputed territory in the South Pacific between Tonga and Fiji.

Alex Mustard / Hedgehog seahorse (Hippocampus spinosissimus) female, portrait. Ambon Bay, Ambon, Maluku Archipelago, Indonesia. Banda Sea, tropical west Pacific Ocean.

Linda Pitkin / Porcupinefish (Diodon hystrix) on coral reef Klein Bonaire, Bonaire, Leeward Antilles, Caribbean.

Alex Mustard / Hedgehog seahorse (Hippocampus spinosissimus) attached to a small soft coral. Anilao, Batangas, Luzon, Philippines. Verde Island Passages, Tropical West Pacific Ocean.

Franco Banfi / Spotted porcupinefish (Diodon hystrix) between the plates of the Salvatierra wreck, Sea of Cortez, Baja California, Mexico, East Pacific Ocean

Constantinos Petrinos / Black-spotted Porcupinefish (Diodon hystrix) poisonous species, Lembeh Strait, North Sulawesi, Indonesia.

Constantinos Petrinos / Black-spotted Porcupinefish (Diodon hystrix) poisonous species, Lembeh Strait, North Sulawesi, Indonesia.

Pascal Kobeh / Common porcupinefish (Diodon hystrix) on coral reef, San Salvador Island / Colombus Island, Bahamas. Caribbean.

Pascal Kobeh / Common porcupinefish (Diodon hystrix) on coral reef, San Salvador Island / Colombus Island, Bahamas. Caribbean.