Figure Eight Puffer - Tetraodon biocellatus

Originates in fresh waters of Southeast Asia, including; Borneo, Malaysian Peninsula, Sumatra and Thailand.

Very few people can resist a puffer fish once they've seen them. Their expressive faces and propeller like fins make them an interesting addition to a freshwater aquarium. Puffer fish derive their name from their ability to inflate themselves with water or air when startled (a defensive mechanism - it's harder to swallow a large fish than a small one).

Figure 8 Puffers are small in terms of puffer fish, reaching an adult size of less than three inches. They are deep brown in color on the upper portion of the body, and white on the underside. Yellow spots and lines are sprinkled throughout the body. Their name is derived from markings across the back that resembles a figure eight.

Even when not startled, Figure 8 Puffers have a roly-poly appearance. You can easily spot a well fed puffer by its rounded belly. Puffers have two pairs of teeth, each of which are fused together giving it a beak-like appearance. This unusual arrangement of teeth gives it the ability to crush hard materials such as the shells of crustaceans. These teeth grow throughout the life of the Figure 8 Puffer, and must be ground down to keep them from being too long. For this reason, they need hard-shelled foods to help keep their teeth the proper length.

Generally puffers are not well suited to a community tank because they tend to be aggressive. Even puffers who have previously been docile can become aggressive as they age, or if they are not well fed. I've had puffers who got along very well for long periods of time and then suddenly turned on their tank mates and chewed them to pieces. On the other hand, most owners have found Figure Eights more peaceful than any other puffers and some have successfully kept them in a community tank.

Ideally Figure 8 Puffers should be kept alone, or in a large aquarium with only a few other fish who thrive in the same habitat. Those that have kept them in brackish water find that Bumblebee Gobies, Knight Gobies, and Mollies are suitable companions. Owners keeping them in freshwater aquariums have reported keeping them with a range of fish, from Barbs to Sharks, to Tetras. I believe in these cases, the habitat has allowed sufficient space to keep the Figure 8 Puffers from feeling threatened. As a rule of thumb, don’t expect to successfully keep them in a typical freshwater community tank.

Controversy exists over whether or not any puffers are actually true freshwater fish. I believe the Figure 8 Puffer to be one of the few that falls in that category. They originate in the fresh waters of the Southeast Asia region, and although they tolerate brackish or even full saltwater, mine have always fared better in freshwater. Others have reported the opposite, stating that salinity in the range of 1.005 to 1.008 will significantly extend the lifespan of the Figure 8 Puffer. Although I have not seen scientific data to support that, I have also not seen data on lifespan in captivity when kept in fresh water.

Figure 8 Puffers prefer a neutral pH and tolerate soft to moderately hard water. Keep the water temperature on the warm side, around 78 degrees F. The minimum tank size should be 15 gallons for a single specimen, more if possible. Filtration should be robust, as Figure 8 Puffers tend to leave a lot of debris from eating. They are sensitive to ammonia, nitrites and nitrates, and will not do well in a tank that is still going through the start-up cycle. Frequent water changes to maintain pristine water conditions are recommended for this fish.

Figure 8 Puffers require ample open space to swim, but also need places to hide and explore. They can be hard on plants, due to aggressively attacking their food, which often falls on plants and other aquarium décor. Decorate the tank with sturdy plants, and be aware that you may need to replace them from time to time.

The dietary needs of Figure 8 Puffers are perhaps one of the more demanding aspects of keeping this fish. Flake or dried foods do not meet their dietary needs. Instead they must be fed meaty and hard-shelled foods such as clams, crayfish, crickets, daphnia, krill, mollusks, oysters, plankton, scallops, snails, shrimp, and worms.

Because the beak of the Figure 8 Puffer can become overgrown, it is important to include plenty of hard-shelled foods in their diet to keep their teeth from overgrowing. In nature, they typically eat crustaceans. Although live foods are ideal, some owners, me included, have had success training their figure eight puffer to eat some frozen foods. Be sure to select high quality frozen foods.

Even for experts, it is nearly impossible to sex Figure 8 Puffers. The most certain way to sex them is to see the female lay eggs, which is an extremely rare occurrence. Only a few cases of spawning in captivity have been reported.

Little is known about how to breed Figure Eight Puffers. In the rare occasions they have spawned in captivity, they have laid eggs on a flat surface, such as the substrate. The male guards the fish for approximately a week until the fry are free swimming. If you have successfully spawned them, please write to me and share your experience.