There are few fish as endearing as Arothron nigropunctatus (aka blackspotted pufferfish or dogface pufferfish), with its big expressive eyes and pouty little mouth. It is one of those fish purchases you could easily be made on impulse, leaving the aquarist with regret once he or she finds out what is involved with keeping this attractive but demanding species.
Difficulty: Pufferfish can present aquarists with some specific challenges that the casual fishkeeper may not be interested in dealing with. One of the biggest issues is tooth growth. The teeth are naturally worn down when these pufferfish feed on coralline algae and stony corals. In the aquarium, pufferfish often don’t get enough of these types of foods and thus the teeth continue to grow to the point where they become nonfunctional.
Physical description: The blackspotted pufferfish comes in a number of different colors. The most common form is gray overall, with brown on the chin and a white band just below the eyes. There is also a lemon-colored pufferfish that is mostly bright yellow with a gray back (this is less common and tends to cost a lot more than the gray-colored fish). On rare occasions, you will even find a blackspotted pufferfish that is light bluish gray overall or even black. All the color forms are peppered with small black spots. This species is very similar to the panda puffer (A. diadematus) from the Red Sea. The blackspotted pufferfish reaches a maximum length of around 12 inches.
Range: The blackspotted pufferfish is found from East Africa to the Samoan Islands. It is found on fringing reefs, lagoon patch reefs and reef faces at depths of 10 to 85 feet. Sponges and stony corals are two of their favorite foods.
Compatibility: The blackspotted pufferfish does well in an aquarium with moderately aggressive aquarium inhabitants (e.g., angelfish and surgeonfish). Once it has acclimated, the aquarist can even give it a go with more pugnacious fish, such as triggerfish. Because it is not aggressive, it can even be housed with more peaceful species, although it will sometimes attempt to eat small, benthic fish, such as gobies. The blackspotted pufferfish should never be housed with ambush predators, such as frogfish and scorpionfish, as these pufferfish will sometimes chew on these stationary fish as if they were encrusted substrate.
An occasional blackspotted pufferfish might nip the ventral surfaces or fins of other fish, especially those species with long, flowing finnage (e.g., batfish). Pufferfish are also opportunistic and many species will feed on sick, dying or distressed fish. The blackspotted pufferfish is a threat to most species of invertebrates and will eat snails, sea urchins, crustaceans (including ornamental shrimp) and even stony corals and sea anemones.
Aquarium conditions: The blackspotted pufferfish will do best in an aquarium of at least 75 gallons. Provide it with several cervices to retreat to or to slumber in at night. Adult blackspotted pufferfish might destroy aquarium décor, as they have been known to chew up faux corals or bleached stony coral skeletons (however, they are less likely to than are larger Arothron spp.). Acceptable water parameters for the blackspotted pufferfish are a pH of 8.1 to 8.4, specific gravity of 1.019 to 1.025 and a water temperature of 74 to 82 degrees Fahrenheit.
Care considerations: Sometimes the blackspotted pufferfish will waste away, even if you feed it frequently. This may be a case of the fish having internal parasites (namely, nematodes in the alimentary tract). Feed your blackspotted pufferfish some food laced with the drug fenbendazole, which will have to be acquired from your vet. This can be done by mixing up your own gelatin-based food and adding this drug at a concentration of 1 percent active ingredient (e.g., one-half gram of drug to 49 grams of food, gelatin mix and water). Give your blackspotted pufferfish the medicated food twice, waiting one week between treatments. If a blackspotted pufferfish does not eat, you can also give it a shot of vitamin B-12 in its dorsal musculature, which can increase its appetite.
You should never encourage your blackspotted pufferfish to inflate. In fact, be very careful when you transfer this fish from one aquarium to another, as they may ingest air, which can be difficult for them to expel. To avoid this problem, be sure to use a specimen container to transfer fish from aquarium to aquarium.
Breeding: The blackspotted pufferfish has not been reported to spawn in captivity.