Figure Eight Puffer Care Guide: Brackish Personality in a Small Tank

Pufferfish pack more personality per centimetre than almost any other aquarium fish, and the figure eight puffer delivers that charm in a manageable package. This figure eight puffer brackish care guide covers the essentials of keeping Dichotomyctere ocellatus in Singapore home aquariums. At Gensou Aquascaping, we have helped many hobbyists set up dedicated brackish tanks for these intelligent, curious fish — and the results are always rewarding.

Species Profile

Named for the figure-eight-shaped markings on its back, this puffer reaches about 6-8 cm in captivity. Originating from Southeast Asian river estuaries, it thrives in low-end brackish water rather than full marine or pure freshwater conditions. Figure eight puffers are widely available in Singapore, with prices typically between $8 and $18 SGD at shops around Serangoon North and C328 Clementi.

Brackish Water Setup

The single most important aspect of figure eight puffer care is providing genuine brackish water. Target a specific gravity of 1.005-1.008 using marine salt mix — not aquarium salt or table salt. Use a hydrometer or refractometer to measure salinity accurately. Mix the salt with dechlorinated water before adding it to the tank. Singapore’s PUB tap water is chloramine-treated, so a quality water conditioner that neutralises both chlorine and chloramine is essential.

Tank Size and Decor

A single figure eight puffer needs a minimum of 80 litres. Despite their small size, these fish are active swimmers with a high bioload due to their meaty diet. Aquascape with smooth rocks, driftwood, and hardy plants like Java fern and Anubias, which tolerate low-end brackish conditions. Avoid sharp decorations — puffers lack scales and are prone to skin injuries. A sand substrate is preferable to gravel for the same reason.

Diet and Beak Maintenance

Feeding is where figure eight puffers demand the most attention. They possess a hard beak that grows continuously and must be worn down through hard-shelled foods. Offer pond snails, Malaysian trumpet snails, frozen shellfish (cockles, mussels), and occasional small prawns. Without regular access to crunchy foods, the beak can overgrow and prevent the fish from eating — a condition that is difficult to correct and often fatal. Feed once daily, removing uneaten food promptly.

Temperament and Tankmates

Figure eight puffers are semi-aggressive and best kept as the sole centrepiece fish. While some hobbyists house them with fast-moving brackish species like mollies or bumblebee gobies, fin-nipping is always a risk. Tankmates should be chosen carefully and monitored closely during the first week. A species-only tank is the safest approach — and honestly, the puffer’s personality is captivating enough to carry a tank on its own.

Water Parameters and Maintenance

Maintain temperature between 25 and 28 degrees C — easily achieved in Singapore’s tropical climate, though a heater provides stability during cooler rainy periods. Keep ammonia and nitrite at zero, and nitrate below 20 ppm. Weekly water changes of 25-30 percent are recommended given the high bioload. Always match the salinity and temperature of new water to the tank before adding it. A powerful filter rated for double the tank volume helps manage the waste these messy eaters produce.

Common Health Concerns

Internal parasites are common in wild-caught specimens, manifesting as a thin body despite regular feeding. A veterinary-grade anti-parasitic treatment during quarantine addresses this proactively. Skin infections can occur if water quality lapses or the fish sustains an abrasion. Maintaining pristine water conditions and a smooth-surfaced environment prevents most issues. With attentive care, figure eight puffers can live eight to ten years — a genuine long-term companion.

Related Reading

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• How to Mix Saltwater for Your Aquarium at Home
• Marine Nitrogen Cycle vs Freshwater: Key Differences You Must Know