Blue Pelagic Porcupine Puffer

Blue Pelagic Porcupine Puffer: The Open Ocean Dweller

The Blue Pelagic Porcupine Puffer (Diodon eydouxii), also known simply as the Pelagic Porcupinefish, is a rare and unique species, highly sought after for its distinctive coloration and unusual open-ocean lifestyle. Unlike most porcupinefish, which are bottom-dwellers, this species is pelagic, spending its life swimming in the open water column, often near the surface, across all tropical oceans.

This puffer is easily distinguished by its smaller adult size, reaching approximately 10 to 11 inches (25-27 cm), and its beautiful coloration: a blue to steely-gray back and sides contrasting with a silver or white underside, often marked with numerous small, dark spots. This more streamlined body shape is an adaptation for its high-water environment.

The Blue Pelagic Porcupine Puffer is an intelligent and engaging fish, but it requires a very large aquarium, ideally 125 gallons or more, to accommodate its active swimming habits and significant bioload. Like all members of the family Diodontidae, it possesses sharp, protective spines that stand erect when the fish inflates its body with water when threatened. Due to the high risk of internal air ingestion, this fish should never be captured with a net; a clear container should be used for all transfers.

Diet & Compatibility:

• Diet: As a Carnivore, this puffer's continuously growing beak requires a diet rich in hard-shelled invertebrates to wear down its teeth. In the aquarium, feed a variety of meaty, crunchy foods, including shell-on clams, mussels, hard-shelled shrimp, krill, and commercial pellets or paste designed for puffers. Failure to provide hard food will lead to an overgrown beak, making it unable to eat. Feed multiple times per day due to its high metabolism.
• Housing Requirements: A large tank with securely placed rockwork is necessary for exploration and shelter, but ample open space is critical for swimming. Due to their messy nature and high waste production, exceptional filtration (oversized protein skimming and regular large water changes) is mandatory. Many keepers prefer a bare-bottom tank to simplify the cleanup of uneaten food and detritus.
• Reef Compatibility: It is NOT Reef Safe. Like its relatives, the Blue Pelagic Porcupine Puffer will use its strong beak to consume virtually all ornamental invertebrates, including crabs, shrimp, snails, and sea stars. While often ignoring large corals, they may nip or damage them while hunting or "sampling" the environment. Best housed in a Fish Only With Live Rock (FOWLR) system.
• Temperament: It is Semi-Aggressive / Assertive. It can be housed with larger, robust, and fast-swimming fish (e.g., large Tangs, Angels, or peaceful Triggerfish) that are too quick for it to bully. However, it should not be kept with smaller, slow-moving, or long-finned species, which it may nip. It is generally best kept singly.

Quick Facts

• Scientific Name: Diodon eydouxii
• Primary Common Name: Blue Pelagic Porcupine Puffer
• Other Common Names: Pelagic Porcupinefish, Deep Blue Puffer
• Origin: Circumtropical (Atlantic, Pacific, and Indian Oceans)
• Max Size: 10-11 inches (25–27 cm)
• Temperament: Semi-Aggressive / Assertive (Active Swimmer)
• Diet: Carnivore (Requires hard-shelled foods)
• Minimum Tank Size: 125+ Gallons
• Reef Compatibility: No (Will eat invertebrates)