Figure 8 Puffer Fish Care (Dichotomyctere ocellatus)

figure 8 puffer fish

Last updated on September 4th, 2022 at 05:39 am

The figure 8 puffer fish, also known as the figure 8 pufferfish or the freshwater puffer, Dichotomyctere ocellatus, or Tetraodon biocellatus, was discovered by Austrian ichthyologist Franz Steindachner in 1907. The name pufferfish comes from the creature’s ability to inflate its body with water or air to protect itself from predators and to help it move about on land. Dichotomyctere ocellatus is an omnivorous fish that can grow up to 3.1 inches long and weigh up to seven ounces.

Dichotomyctere ocellatus is a freshwater member of the Tetraodontidae family of puffers. Its name comes from the distinctive pattern on its skin, which resembles the number eight on its side and top, with an oval shape around it that resembles an eye.

It lives in shallow coastal waters around Japan and has an oval-shaped body that allows it to hide within small crevices.

Origin and descriptions

figure 8 puffer fish

The figure 8 puffer fish is a type of tetraodon biocellatus. It has a brownish coloring and is native to the marine environments of Australia, Indonesia, Malaysia, Papua New Guinea, the Philippines, and Vietnam.

Although it looks harmless, it is considered one of the most dangerous types of marine life due to its toxicity levels which can be potentially fatal if eaten by humans. The figure-8 puffer fish lives at depths of .1-.6 meters below sea level, but will also venture out into tidal areas when searching for food.

Its diet consists mainly of small invertebrates such as crustaceans and mollusks, but will also eat algae when necessary. They are very territorial creatures that are known to engage in battles with other figure-8 puffers for food or territory.

Species profile

The figure 8 puffer fish belong to the family Tetraodontidae, which includes other familiar species such as porcupinefish and balloonfish. Also known as a toothless or blind puffer fish, Tetraodon biocellatus is found in shallow waters along Australia’s east coast.

Gold Dust Molly (Poecilia sphenops)

They have been observed swimming at depths of up to 2 meters (6 feet) but typically remain within 30 centimeters (1 foot) of the ocean floor. Although they prefer warm water temperatures between 16 and 26 degrees Celsius (61–79 degrees Fahrenheit), they can survive in cooler temperatures.

Figure 8 puffer fish feed on crustaceans, mollusks, sea urchins, small fish, and algae. As their name suggests, figure-8 puffers have an unusual body shape with an oval cross-section that makes them resemble a figure eight lying on its side.

Scientific name

The scientific name of the figure 8 puffer fish is Tetraodon biocellatus


Dichotomyctere ocellatus

Common names

The figure-8 puffer fish are also referred to as brackish puffer fish, eyespot puffer fish, figure eight puffer fish, or just eyespot puffer.


Figure 8 puffer fish are native to Southeast Asia from Indonesia to Thailand, where they live in brackish (slightly salty) waters. Sometimes they can be found in nearby freshwater too. They prefer rivers and coastlines that are calm and slow-moving.

Figure 8 puffer fish size

figure 8 puffer fish

Figure 8 puffers grow to about 3.1 inches (8 cm) in length.

Tank size

Since they are averagely sized, the minimum recommended tank size is 15 gallons (57 liters).

Tank requirements

Figure 8 puffer fish should be kept in a tank of at least 15 gallons with lots of live rock and some shelter like caves. A mature figure-eight puffer can grow to around 3.1 inches, so your setup will need to be quite large, especially if you plan on getting more than one of these fish.

Figure eight puffers prefer water temperatures between 72°F and 82°F (22°C to 28°C) and pH levels between 7.8 and 8.4. They also require a lot of oxygen, so they cannot be kept in tanks that have low flow or poor circulation. Because they are very active swimmers, they require strong filtration systems.

Indian Glass Fish (Parambassis ranga)

Figure eight puffer fish eat crustaceans and invertebrates such as brine shrimp, krill, mysid shrimp, copepods, and amphipods. This species is not reef safe because it may nip at corals or other sessile invertebrates.

Tank mates

The ideal habitat for a figure 8 puffer fish is a large aquarium with only a few other fish that prosper in the same partial-saline conditions. The bumblebee gobies, knight gobies, and mollies are excellent tank mates for owners who keep figure 8 puffer fish in brackish water.


figure 8 puffer fish

It has been reported that they lay eggs on a flat surface, such as the substrate, on rare occasions when they have spawned in captivity. Males guard eggs for approximately a week until the eggs hatch and the fry are free to swim.

Are they aggressive or peaceful?

Figure-8 puffer fish are actually non-aggressive but poisonous. They only inflate their bodies as a defense mechanism when they’re threatened. In fact, it’s quite hard to make one inflate itself in captivity; some people say that you can do it by poking them with a stick, but we’ve never had any luck with that approach.

Figure 8 puffer fish care

Figure-8 puffer fish are very social and need constant interaction with other members of their species. As such, they require at least a 30 gallon tank when kept in pairs. A 200 gallon tank is recommended for keeping them in a school. They prefer water that has been aged for several days prior to adding it to their tanks since younger water can make them susceptible to disease.

The pH level should be between 6.5 and 7.0, while the temperature should be maintained between 75–82 degrees Fahrenheit (24–28 degrees Celsius). Figure 8 puffers do not like strong currents or high levels of waste products in their water, so avoid overfeeding your pet or adding live plants to its environment if you want your fish to thrive.

Reedfish, Rope Fish (Erpetoichthys calabaricus)

What they eat

Figure 8 puffer fish (dichotomyctere ocellatus) are omnivores, which means they will eat both plants and animals. They feed primarily on algae and small invertebrates that they find at or near coral reefs. Their omnivorous diet is great because it provides them with nutrients lacking in their natural habitat. This feature makes them highly compatible with reef-keeping tanks and is a key to keeping figure 8 puffer fish healthy in captivity.


figure 8 puffer fish

With good care and normal water conditions, the figure 8 puffer fish can live up to 15 years.

Parasites and diseases

Dichotomyctere ocellatus is very susceptible to parasites and diseases. As with most things, they are more likely to be affected by any illness when stressed or in poor environmental conditions. If you find your puffer fish at a pet store, immediately quarantine it for three weeks before adding it to your tank, as some stores often do not properly care for their animals.

During that time, treat it with copper sulfate or an equivalent treatment. Copper sulfate will kill many of the parasites that may have been on your new puffer fish while in captivity. After three weeks of being treated, put your new puffer into your main tank along with all of your other healthy fish.


The tetraodon biocellatus, or figure 8 puffer fish, is a solitary fish that is rarely seen in large groups. They are relatively small and get to only be around 3.1 inches long, which means they don’t have much to fear from predators while they’re swimming around in their ocean habitat. The threat of being attacked by a predator is very low for this fish, but what they have to watch out for is other humans.

Some common predators are Humans, Seals, Sharks, Dolphins, Swordfish, and more.

Do they make good pets?

Although they look cute, puffer fish are not good pets and may be illegal in some areas. For example, New York state prohibits keeping any species of pufferfish as pets. If you’re interested in an aquarium pet, it’s best to talk to a professional first and do plenty of research before deciding which one is right for you. Your local fish store can help provide resources to learn more about your options.

Pea Puffer Fish (Dwarf Puffer Fish)

With so many fish available to choose from, there’s no reason why anyone shouldn’t find something perfect for their home or office. Be sure to think through what kind of environment you have available, how much time you want to spend on maintenance, and other factors that might influence your decision when picking out a new addition.