Figure Eight Puffer

The Figure Eight Puffer (Dichotomyctere ocellatus) is one of the most recognizable pufferfish in the aquarium hobby, instantly identifiable by the vivid black-and-yellow figure-eight markings adorning its dorsal surface. Native to the coastal and estuarine regions of Southeast and South Asia, this species thrives in brackish conditions, though it can adapt to a range of salinities. Reaching up to 8 cm in length, it is compact yet full of personality — widely regarded as one of the most interactive and expressive fish an aquarist can keep.

Its body is rounded and scaleless, with the characteristic ability to inflate when threatened. The eyes are highly mobile and give the fish a remarkably alert appearance. Males tend to display more vivid coloration than females, and both sexes will investigate their surroundings with apparent curiosity.

In the aquarium, the Figure Eight Puffer is best housed alone or with robust, fast-moving tank mates that can tolerate its nippy nature. It is an obligate carnivore that requires hard-shelled foods such as snails, clams, and crustaceans to naturally wear down its ever-growing beak. Without appropriate diet, dental overgrowth can become a serious health issue requiring intervention.

This species is not recommended for community tanks due to its aggressive and territorial tendencies. It thrives best in a well-decorated brackish aquarium with plenty of hiding places, visual barriers, and enrichment to satisfy its inquisitive nature. Given proper care, the Figure Eight Puffer becomes a deeply engaging centerpiece fish with a lifespan of up to 10 years.

Tank Setup Provide a minimum of 80 liters for a single Figure Eight Puffer. Brackish conditions are strongly preferred — aim for a specific gravity of 1.005–1.010. Use a sandy substrate and decorate with rocks, driftwood, and robust plants like Java fern or Anubias. Caves and visual barriers help reduce stress and territorial behavior.

Water Parameters Maintain pH between 7.0 and 8.0 and temperature between 23°C and 28°C. Regular partial water changes of 25–30% weekly are essential to maintain water quality, as puffers are messy eaters. Use a good canister or hang-on-back filter with adequate flow.

Diet Feed a varied carnivorous diet consisting of snails (ramshorns, bladder snails), clams, mussels, krill, and frozen bloodworms. Hard-shelled prey is critical to keep the beak trimmed — overgrown teeth can prevent feeding and require manual trimming under anesthetic. Feed adults every other day to avoid obesity.

Compatibility The Figure Eight Puffer is aggressive and nippy and should not be kept in community tanks. If kept with other fish, choose fast, robust brackish species. Males can be territorial toward one another. A species-only setup is most reliable.

Behavior and Enrichment This species is highly intelligent and can become bored without environmental enrichment. Rearranging decorations, varying feeding methods, and introducing live prey occasionally all help keep the fish mentally stimulated. They will often track their owner's movements along the glass.

Health Notes Monitor beak length regularly. Watch for signs of internal parasites, which are common in wild-caught specimens. Ich and bacterial infections can occur if water quality lapses. Quarantine all new fish before introduction.