Figure 8 Pufferfish (Tetraodon biocellatus) is a small, brackish-water puffer known for its unique personality and striking appearance. Native to Southeast Asia, particularly rivers and coastal regions of Thailand, Malaysia, and Borneo, this species is a favorite among aquarists who enjoy interactive and intelligent fish. Unlike many other puffers, the Figure 8 stays relatively small, making it a popular choice for those looking for a manageable puffer species.

Appearance
The Figure 8 Pufferfish gets its name from the distinct black patterns on its back that often resemble the number 8. Its body is greenish-yellow with dark markings and a pale underside. Adults typically reach around 3 inches in length, making them one of the smaller pufferfish species. Their expressive eyes and ability to inflate when threatened add to their unique charm.

Behavior
These puffers are intelligent, curious, and often recognize their owners. They are known for being interactive, sometimes even begging for food at the front of the tank. However, they can also be territorial and nippy, making careful consideration of tank mates important. While not as aggressive as larger puffers, they should never be kept with small, slow, or long-finned fish.

Tank Requirements
A single Figure 8 Puffer should be housed in at least a 15–20 gallon tank, with larger tanks required for multiple puffers. They thrive in brackish water conditions, which means a small amount of marine salt should be added to the water. The aquarium should have plenty of hiding spots, driftwood, rocks, and plants to reduce stress and provide enrichment. A secure lid is also necessary, as puffers can jump.

Water Parameters
Temperature: 75–82°F
pH: 7.0–8.0
Salinity: Low-end brackish, around 1.005–1.008 specific gravity

Maintaining stable, clean water is crucial, as puffers are sensitive to poor water conditions. A strong filter and frequent water changes are highly recommended.

Diet
Figure 8 Puffers are carnivores with strong beaks that continuously grow. To keep their teeth trimmed and prevent overgrowth, they must be fed hard-shelled foods regularly. Their diet should include snails, shrimp, clams, mussels, and crabs. They will also eat frozen or live worms and other meaty foods. A varied diet is essential for their health and dental maintenance.

Tank Mates
Because of their nippy and territorial nature, tank mates should be chosen with caution. Many aquarists prefer to keep them in a single-species tank. If kept with others, possible companions include fast-moving brackish fish such as bumblebee gobies, mollies, or knight gobies. Avoid keeping them with slow or delicate fish, as they are likely to be harassed.

Challenges in Keeping Figure 8 Puffers
The biggest challenges are their need for brackish water, specialized diet, and territorial behavior. Their care requires commitment, especially in maintaining water quality and providing proper foods for their dental health. They are not suited for beginner aquarists but can be very rewarding for those willing to meet their needs.

Conclusion
The Figure 8 Pufferfish is a fascinating and entertaining species that brings personality and activity to any aquarium. With their bright markings, intelligence, and curious behavior, they quickly become a favorite among fish keepers. While they require special care and attention, those who can provide the right environment and diet will find the Figure 8 Pufferfish to be an engaging and unique addition to their aquarium.