Bennett’s Sharpnose Pufferfish – Facts and Photographs

The Bennett’s Sharpnose Pufferfish (Canthigaster bennetti) is also known as Bennett’s Pufferfish, the Whitebelly Pufferfish, Bennett’s Toby and the Exquisite Toby. As with many other puffers, they have a symbiotic relationship with types of bacteria such as Pseudoalteromonas tetraodonis. This bacteria produces tetradotoxin which is a powerful neurotoxin. These tetradoxin’s are found in their skin and internal organs. Tetradoxin is approximately 100 times more toxic than cyanide. This provides the fish with protection against predators.

APPEARANCE

Bennett’s Sharpnose Pufferfish have a typical pufferfish shape with a rounded body and a short tail. They have no scales or lateral line. The skin is thick and tough. The body background color is usually a light white grey on the lower body while the upper body is an olive green colour. The entire body has small blue-green dots spread across it and there are light brown squiggles on the upper body. There are also oval black marks around the dorsal fin that are ringed in blue green lines. Around the rear of the eye there are blue lines which extend forward onto the upper lip. The lower facial area has brown dots on it.

They have the ability to lighten their colouration and when seen at night their colours are subdued. Presumably this aids in camouflaging them. As can be seen in the image immediately below when seen from above or behind the dark oval spots around the dorsal fin almost form a heart shape. Full grown they can grow up to 10 cm in length although usually they are slightly smaller.

As with all pufferfish or blow fish as they are sometimes known, they have the ability to take water into their stomach to swell themselves up, making it harder for a predator to fit them in its mouth.

BENNETT’S SHARPNOSE PUFFERFISH IN THE WILD

Bennett’s Sharpnose Pufferfish are usually seen on sandy bottoms with isolated rubble. During the day they are normally seen in pairs over the reef or rubble. If a diver nears them they will usually swim off at a slight angle allowing one of their eyes to point backwards to watch you as can be seen above.

The juveniles are reclusive always staying close to cover and often hide in sea urchin spikes when there is a diver around. The adults sleep on depressions in the sand at night. They are fairly common in Tanzanian waters.

HABITAT

Bennett’s Sharpnose Pufferfish are found across the Indo-West Pacific from the East African coast across to the Galapagos Islands. Usually they are found on the reef and sandy bottoms close to reef and in lagoons and sandy areas with seagrass to a depth of 15 meters.

DIET

Bennett’s Sharpnose Pufferfish have four teeth which are fused into a sharp edged beak and the teeth continue growing throughout their life. For their size they have a powerful bite. They feed on a variety of species of algae, usually green filamentous algae but they have been known to eat red algae. They are thought to supplement their diet with small crustaceans.

REPRODUCTION

Little seems known of their breeding behavior , however in pufferfish, mating is between two distinct individuals and the eggs are released by the female and fertilized by the male. In other Canthigaster species the females prepare nests in toxic algae and after laying there is no parental care. The larvae are planktonic.

AQUARIUMS

Bennet’s Pufferfish have the ability to release toxins into the water when stressed and are not regularly kept by aquarists. However given that they are attractive looking they are kept by some aquarists. Because of their constantly growing teeth, they require regular feeds on hard shelled crustaceans to prevent the teeth from growing too far and becoming unusable. They are not aggressive fish, but may attempt to eat smaller sickly fishes and may nip long finned fishes. They will also eat most invertebrates and may damage corals.