Figure 8 puffer
A small brackish water pufferfish with distinctive eye-like markings.
The figure 8 puffer is a small fish native to Southeast Asian rivers and estuaries. It features unique greenish-yellow patterns resembling the number eight. This species thrives in brackish water and requires specific care in captivity, including hard-shelled foods to maintain its beak.
- Grows to approximately 8 cm in length
- Named for eye-like markings near the tail
- Thrives in brackish water with added marine salt
- Requires hard-shelled foods to maintain beak health
- Can live up to 15 years in captivity
What it is
The figure 8 puffer is a small member of the pufferfish family. Adults reach about 8 cm in length. Their backs display greenish-yellow markings that vary between individuals. The spots near the tail often look like the number eight or eyespots. Like other puffers, it can inflate its body with water or air when threatened. Despite this defence mechanism, it is considered relatively peaceful compared to many relatives.
Where it lives
This species inhabits Southeast Asia. It is found in the lower reaches of the Mekong River in Cambodia. Populations also exist in Peninsular Malaysia and on the island of Borneo, specifically in Sarawak and Kalimantan. While often kept in freshwater tanks, it naturally occurs in areas where fresh and salt water mix.
How it lives
Figure 8 puffers are molluscivores, meaning they eat hard-shelled invertebrates. In the wild, they consume mussels, cockles, oysters and krill. They use a beak-like structure formed from two plates to crush shells. This diet helps keep their teeth trim. In captivity, they may accept flake food, but this should not be their main diet. They are sensitive to poor water quality and require complex tank setups with hiding places to prevent boredom.
Fish and people
Aquarists keep this fish for its unique appearance and behaviour. It requires a tank of at least 15 US gallons with temperatures between 24 and 28 degrees Celsius. The water must be fully cycled to remove harmful nitrites and nitrates. Adding marine salt creates a brackish environment with a pH between 7.8 and 8.3. Snails are often fed to captive specimens to help wear down their growing beaks. With proper care, they can live up to 15 years.
Questions people ask about Figure 8 puffer
Is the figure 8 puffer a freshwater fish?
It is often mistaken for one, but it is euryhaline. It lives best in brackish water with specific gravity between 1.005 and 1.008. It can survive in fresh water but exhibits different physiological traits in saltier environments.
What do figure 8 puffers eat in captivity?
They are molluscivores and need hard-shelled foods like snails, mussels or krill. These items help crush their beak plates and prevent overgrowth. Flake food is not recommended as a primary diet source.
How large does an aquarium need to be?
A minimum tank size of 15 US gallons is required. The setup should include plenty of nooks and crannies to reduce boredom. Over-filtration and frequent partial water changes are necessary due to sensitivity to nitrates.
Good reading and sources
- Dichotomyctere ocellatus on WikipediaEncyclopedia
- More photos on Wikimedia CommonsPhotos
- Wikidata recordOpen data
The facts on this page come from the Wikipedia article "Dichotomyctere ocellatus", written by its contributors and used under the CC BY-SA 4.0 licence, and from its Wikidata record (CC0). EveryFish rewrote the text in its own words, with AI assistance, and compares every page with the article to make sure no passage is copied. It may be reused under the same CC BY-SA 4.0 licence with a link back.
It may contain mistakes, and figures change over time. Nothing here is investment or buying advice. If something is wrong, tell us. Last refreshed 2026-11-15.
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