Bennett's sharpnose puffer

Canthigaster bennetti, commonly known as Bennett's sharpnose puffer, is widely distributed throughout the tropical Indo-Pacific. Its range extends from the east coast of Africa to the Tuamotu Islands, reaching north to southern Japan and south to the Great Barrier Reef. It inhabits sheltered lagoons, sandy flats, and weed-rich inner reefs, often associated with seagrass beds at depths between 1 and 15 meters.

This species belongs to the family Tetraodontidae and the subfamily Canthigasterinae (sharpnose puffers). It features a compact body, protruding eyes capable of independent movement, and a beak-like mouth formed by the fusion of its teeth. It lacks pelvic fins and has a smooth skin covered in tiny prickles that become erect when the fish inflates.

Canthigaster bennetti is a solitary and moderately territorial fish. It spends its time hovering slowly over the substrate, inspecting crevices for food. While generally peaceful toward unrelated fish, it can be aggressive toward other Canthigaster species. When threatened, it can inflate its body by sucking in water to deter potential predators.

The coloration is complex and attractive: the body is greenish to brownish on the back, fading to white on the belly, and covered with numerous small iridescent blue or green spots. Radial blue lines extend from the eyes, and a distinct dark spot (ocellus) is present at the base of the dorsal fin. There is no visible sexual dimorphism between males and females.

Requires an aquarium of at least 150 liters (approx. 40 gallons) equipped with open swimming space and plenty of live rock arranged to create caves and swim-throughs. The rocks provide foraging ground. Efficient filtration and a strong protein skimmer are essential, as puffers generate a significant bioload due to their messy feeding habits.

In the wild, it has an omnivorous diet consisting of algae, sponges, small gastropods, crustaceans, and polychaetes. In captivity, feed high-quality frozen foods like mysis, brine shrimp, whole unpeeled shrimp, and clams on the half shell to help wear down their continuously growing beak. Include algae sheets and spirulina-based preparations.

Demands clean, highly oxygenated water. Maintain temperatures between 24°C and 28°C (75°F to 82°F), with pH between 8.1 and 8.4 and specific gravity stable between 1.021 and 1.025. Regular 10-15% weekly water changes are recommended to control nitrogenous waste. Copper levels must be monitored closely, as they do not tolerate copper medications well.

It is not considered reef-safe, as it may nip at the polyps of stony and soft corals, and will prey on small ornamental invertebrates like shrimp, snails, and crabs. It can coexist with active, medium-sized fish like surgeonfish, clownfish, and wrasses. Avoid slow-moving, long-finned tankmates, which the puffer may nip.

There are no documented cases of successful captive breeding and larval rearing in home aquariums. In nature, they spawn on benthic substrates, followed by a planktonic larval stage in open water. Consequently, all specimens available in the aquarium trade are sustainably harvested from the wild.

Due to their lack of protective scales, they are highly susceptible to skin parasites such as Cryptocaryon irritans (ich) and Oodinium. Under extreme stress, they can secrete tetrodotoxin from their skin, which can poison tankmates if the puffer dies. A quarantine protocol for new arrivals is highly recommended.