🐟 AquaticCare difficulty: IntermediateLegal complexity: Low
Figure 8 puffer
Dichotomyctere ocellatus · also called Figure-eight puffer, Eyespot puffer, Tetraodon biocellatus (former name)
A small, charismatic brackish-water puffer with bold yellow-on-brown figure-eight markings and eyespots near the tail. It is intelligent and personable but has continuously growing beak-like teeth and is best kept alone in low-end brackish water.
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Quick facts
| Size | Small; about 3 in (8 cm). |
| Lifespan | 5–15 years |
| Social needs | solo |
| Native region | Southeast Asia (lower rivers and estuaries, e.g. Mekong region) |
| Origin | Old World |
| Climate | 🌴 Tropical |
| Water type | 🌫️ Brackish |
| Family | Tetraodontidae |
| Genus | Dichotomyctere |
Part of the Puffers
Intelligent, personable pufferfish with beak-like teeth and special diet and water needs; most are best kept solo.
Habitat & space requirements
From the minimum an animal needs to be kept humanely, up to the ideal setup. Bigger is almost always better — minimums are floors, not targets.
Life & growth stages
How this animal changes through its life — each stage often has its own care, diet and space needs.
Habitat & enclosure
Keep one in a 15-20 gallon (60-75 L) or larger tank; allow more space and only experienced groupings beyond that. Low-end brackish water with a specific gravity around 1.005-1.008 (roughly 5-12 g/L marine salt), pH 7.5-8.2, temperature 75-82F (24-28C). Provide gentle flow, plenty of caves, driftwood, and salt-tolerant plants for cover and to break sightlines. Stable parameters and pristine water matter more than tank decor for this messy eater.
Substrate
Fine sand or smooth gravel works well and lets snails and trumpet snails burrow, providing live 'dental' food. A sand bed also suits the puffer's habit of nosing along the bottom hunting prey. Keep the substrate clean, as puffers are messy, high-waste feeders.
Equipment & setup
Use an efficient filter rated above the tank size to handle heavy waste, a reliable heater, and a hydrometer or refractometer to manage brackish salinity precisely. Marine aquarium salt (not plain aquarium 'tonic' salt) is required to mix the brackish water. Gentle flow and good cover complete the setup; no UVB needed.
Diet
A carnivore and dedicated snail-cruncher. Feed a hard-shelled, varied diet: ramshorn and Malaysian trumpet snails, small clams and mussels, krill, mysis, bloodworms, and chopped prawn. The shells and chitin wear down the puffer's ever-growing beak; without them the teeth overgrow and must be trimmed. Feed small amounts most days and keep a steady snail supply as 'dental' food.
Behavior & temperament
Bold, curious, and interactive, often watching the room and begging at the glass, but also a fin-nipper and territorial toward other fish. It is generally best kept solo; tankmates risk being nipped or killed, and other puffers may fight. Not venomous in the sting sense, but its tissues can carry tetrodotoxin, so it is unsafe to eat (never an issue for an aquarium pet). Not a handling species; it can bite and may inflate if grabbed.
Health
Hardy when water is clean and brackish, but prone to ich, internal parasites (common in wild-caught stock; deworm new arrivals), and obesity from rich foods. The signature problem is overgrown teeth from a too-soft diet, causing inability to eat; provide hard-shelled prey or have the beak trimmed under sedation by a fish vet. Avoid copper at full marine doses; use puffer-safe treatments. Sensitive to nitrate, so keep up large water changes.
Tips, DIY & hacks
Maintain true low-end brackish water with marine salt mixed to a measured specific gravity; pure freshwater shortens this puffer's life. Keep a breeding colony of snails in a separate tank as ongoing tooth-wearing food. Quarantine and deworm new (often wild-caught) puffers. House it alone unless you are experienced; its nipping makes community life risky for tankmates.
Sources
- Seriously Fish: Dichotomyctere ocellatus (reference)
- FishBase: Dichotomyctere ocellatus (database)
- Wikipedia: Figure 8 puffer (wiki)