Figure Eight Puffer Care Guide: Brackish Water Character

The figure eight puffer (Dichotomyctere ocellatus) is one of the most charismatic fish in the hobby. Named for the figure-eight-like markings on its back, this small puffer combines intelligence, personality and striking looks in a compact package. This figure eight puffer care guide from Gensou Aquascaping at 5 Everton Park covers the unique requirements of this brackish water species.

Species Overview

Figure eight puffers are found in brackish estuaries and mangrove swamps across Southeast Asia, including parts of Malaysia and Indonesia. They grow to 6–8 cm and can live up to 15 years with excellent care. Their large, expressive eyes move independently like a chameleon’s, and they quickly learn to recognise their keeper — often begging for food at the glass.

Tank Requirements

A single figure eight puffer needs at least 80 litres, with an additional 40 litres per extra puffer. These fish are intelligent and need environmental enrichment — provide rockwork, driftwood, caves and hardy plants. They spend time at all levels of the tank and appreciate moderate current. A tight-fitting lid is essential, as puffers can and do jump.

Brackish Water Setup

While young figure eights tolerate freshwater, they thrive in low-end brackish conditions with a specific gravity of 1.003–1.008. Use marine salt (not aquarium salt) to achieve this, and measure with a refractometer or hydrometer. pH should be 7.5–8.5, temperature 24–28 °C. Some hobbyists successfully keep them in full freshwater long-term, but longevity and health improve markedly with some salinity.

Diet and Feeding

Puffers have beak-like teeth that grow continuously and must be worn down by hard-shelled foods. Offer snails (pond snails, Malaysian trumpet snails, ramshorn snails) as the primary diet — these are essential for dental health. Supplement with frozen bloodworms, mysis shrimp, cockle, mussel and crab legs. Avoid dried foods, which most puffers refuse. Feed once daily, with snails available at all times.

Behaviour and Personality

Figure eight puffers are curious, intelligent fish that interact with their environment and keeper in ways most fish cannot match. They investigate new objects, watch activity outside the tank and develop distinct individual personalities. However, they can be nippy with tank mates and each other. Watch for aggression, especially during feeding time.

Tank Mates

Keeping figure eight puffers in a community requires caution. The best tank mates are fast-moving, robust brackish species like bumblebee gobies, mollies (which adapt well to brackish water) and knight gobies. Avoid slow-moving or long-finned fish, as puffers are notorious fin nippers. Many keepers find a species-only tank is the most reliable approach.

Health Considerations

Overgrown teeth are the most common issue — if your puffer cannot close its mouth or refuses food, the teeth may need manual trimming by a veterinarian experienced with fish. Internal parasites are common in wild-caught specimens; quarantine and treat with praziquantel if needed. Ich is less common in brackish water due to the salinity, which naturally suppresses the parasite.

Singapore-Specific Tips

Singapore’s proximity to the natural range of figure eight puffers means wild-caught specimens occasionally appear at local fish shops. Always quarantine these for at least four weeks and treat for parasites. Marine salt is readily available at aquarium shops across Singapore. The warm climate eliminates heater concerns, though ensure adequate ventilation in the tank room to manage humidity from evaporation.

Conclusion

The figure eight puffer is not just a fish — it is a pet with genuine personality. Their intelligence, interactive behaviour and unique care requirements make fishkeeping an engaging daily experience. Visit Gensou Aquascaping at 5 Everton Park for guidance on setting up your first brackish puffer tank.