Puffer Fish

Common Name(s): Puffer fish, Puffers, Tobies, Porcupine Fish, Burr Fish, Balloonfish, Blowfish

Scientific Name(s): Numerous

Taxonomy:

Domain: Eukarya

Kingdom: Animalia

Phylum: Chordata

Class: Actinopterygii

Order: TetraodontiformesFamily: Tetraodontidae

Genera: Numerous; Arothron, Canthigaster, and Fugu are of particular commercial interest

Species: Numerous

Description:

On a recent trip to Costa Rica, I had a couple of close encounters with a very cool type of fish known as the porcupine puffer (Diodon holocanthus) (I also encountered actual porcupines, but that is a story for another article). The experience I had with this particular species inspired me to write this edition of Species Spotlight, which discusses puffer fish as aquarium inhabitants. For some, it might be surprising to learn that puffer fish can be very good livestock for the right aquarist sporting the proper setup. Though I would generally categorize them as an advanced level fish it is not because they are not hardy, but more because their tankmates and system should be selected with care. Moreover, their distinct habit of puffing up like a water balloon when disturbed should be avoided, though it is such a recognizable trait that it gives the fish their common name.

Puffer fish always catch my eye because they have cute faces and endearing personalities. Unlike many fish, they tend not to be elusive and can develop a rapport with their keepers. In the wild, it is often possible (though not advisable), to simply swim up to a puffer fish and grab it. While in Costa Rica, I made countless observations of porcupine puffers and other co-habitating puffer species, often in extremely shallow waters of no more than 6 inches! These fish seemed completely unperturbed by my lumbering presence on the rocks just above them.

What makes puffers even more interesting is their celebrity status as the Fugu fishthe shining star of risky foods. Many puffers have toxic skin and internal organs that contain potent and deadly forms of tetrodotoxins and saxitoxins. Fugu, the japanese delicacy, is made from select cuts of puffer fish, prepared in specificand hopefully safeways. People choosing to take a risk on fugu are usually seeking the characteristic lip and tongue numbing sensation, though more than a few have died when the fish was poorly prepared or the wrong parts were served. Amazingly, toxin free fugu made from farmed puffer fish is now available, as the fishs diet seems to be the mitigating factor for toxicity. Puffer fish toxin has also been implicated as the primary component of a coma inducing powder used in certain religious practices.

Another great thing about puffer fish is that they have a cool, unique look to them that really is unlike most other fish encountered in the aquarium. They do bear a superficial resemblance to boxfish, yet they lack the rigid body that gives these others their shape. Instead, puffers have the ability to rapidly suck in water and expand their flexible skins into the shape of a large round ball. Porcupine puffers, and others with spines, inflate when threatened and deter predatorial attacks by becoming a very unappealing mouthful. When not inflated, puffers usually have big round eyes protruding from a flattened face, though some have a snout that resembles that of a dog. The teeth on each jaw are fused into two course grinding plate; one on the top and one on the bottom. They have robust, squarish bodies with reduced fins. The dorsal and anal fins are usually in line with each other and just anterior of the narrow caudal peduncle. A few can come in marvelous colors as well, with blues, greens, and yellows that can rival that of any wrasse. Often, the most colorful puffers are the smallest, belonging to the genus Canthigaster and referred to as Tobies. By contrast, the larger genera tend to be spotted, striped, or mottled combinations of blue, black, white, tan, and brown.

Ecology:

Pufferfish are basically ubiquitous in tropical and sub-tropical waters. Some live in the extreme shallows, while others may range down to several hundred feet deep. In at least one case, that of Diodon holocanthus, a single species is found in multiple oceans and in waters ranging from equatorial to as a far north as Southern California. However, many species do prefer to inhabit nearshore and/or shallow coral reefs. Such areas provide both cover and ample invertebrate food sources.

Puffers obviously reproduce sexually, and may form pair bonds as opposed to broadcast spawning. However, the eggs of many are still pelagic and thus remain unattended by the parents after fertilization. In a few alternative cases, nesting behavior is observed. Farming puffer fish, especially Fugu species, has become a well-established means of obtaining non-toxic specimens for Asian cuisine. Of course, the ability to captively-rear puffers has implications for the aquarium trade as well.

Aquarium Care:

Proper aquarium care for puffer fish starts with the introduction. With puffers, there are two immediate concerns. The first thing to consider is that any transfer of the fish from one container to another must be done underwater. Allowing a puffer to inflate itself with air can lead to its death. If you are working with a porcupine puffer, using a net is a bad idea. Instead, try coaxing the fish into a plastic or glass vessel that you can then lift out of the water while it is full. The second consideration is that puffers can be susceptible to marine ich and other parasites because they lack scales. Therefore all puffers should undergo quarantine for up to six weeks before being introduced into a display tank.

In addition to safely introducing a new puffer fish into an aquarium system, care should be taken when selecting the livestock it lives with and the size of the tank it inhabits. Puffer fish are not reef-safe. They prey on invertebrates, including corals, mollusks, and echinoderms. Their crushing teeth-plates enable them to make short work of scleractinian skeletons, snail shells, and shrimp exo-skeletons, so they are only suitable for fish-only systems. Fortunately, most puffers are fairly docile and they get along well with other fish. The exceptions are the porcupine fish, which may hunt and eat smaller fish, and nip at the fins of larger ones at night. There are also some species, especially Tobies, which are aggressive with conspecifics, and should only be kept singly or as a member of a mated pair. Tank size, on the other hand, matters as much as tankmates because many species, such as the white-spotted (Arothron hispidus), guinea-fowl (A. meleagris), and Long-Spine porcupine puffer (Diodon holocanthus) can grow up to twenty inches long. You only need to imagine a twenty-inch beach ball swimming around in your tank to understand why it must be very large to accommodate certain species. The small size and great coloration found in tobies, which generally do not exceed five inches, makes them an attractive alternative to some of the bigger varieties.

Once the requisite conditions are met, puffers are not particularly challenging. They will adapt well to normal aquarium conditions. Since many puffer fish species have relatively large native ranges, individuals may hail from a broad variety of temperature and depth profiles, and transition to the aquarium will be eased if these native conditions can be duplicated. The tanks aquascaping should include large, open swimming areas, along with accessible rocky hiding places. Most species will do fine with moderate lighting, but Diodon spp. spiny puffers prefer bright illumination. Over time, the majority of puffers will do quite well in an aquarium with good upkeep. Also, remember to keep electrical cords protected from puffer fish; they have a penchant for chewing through them, with shocking results!

Puffer fish also eat a lot, and they can be messy. Diets vary from corallivorous to herbivorous, but few are picky. They may choose to be discriminating when first introduced, so live shrimp and mollusks should be offered, but puffers should rapidly adapt to eat most offerings. A good omnivorous mixture of algae, shrimp, and hard-shelled mollusks such as snails will provide both good nutrition and the means to grind down the fishs ever-growing beak of fused teeth. Due to the large quantity of food that must be provided to puffer fish, their system should include strong filtration and adequate water flow. It is advisable to utilize protein skimming and a regularly maintained mechanical filter. In addition, the puffers susceptibility to parasitism can be reduced through the use of UV sterilization and the dietary additions of garlic and omega-3 fatty acids.

Quick Notes:

• Transfer puffer fish underwater; never let them inflate with air
• Puffers are not reef-safe and must be kept in fish-only systems
• Provide puffers with hard-shelled food to help keep their beaks ground
• Keep electrical cords protected from nibbling puffers
• Most puffer require very large tanks, but Canthigaster spp. Tobies are small enough for many home aquaria

Works Cited:

Champlin, J. Puffer Care and Information. Wet Web Media Online. URL: < http://www.wetwebmedia.com/puffcareinfo.htm >

Jennings, G. The New Encyclopedia of the Saltwater Aquarium. Buffalo: Firefly books Ltd., 2007.

Lieske, E. and R. Meyers. Coral Reef Fishes, Revised Edition. Princeton University Press: Princeton, 2001.

Matsui, T., et al. Comparison of Toxicity of the Cultured and Wild Puffer Fuge Niphobles. Bulletin of the Japanese Society of Scientific Fisheries, 48: 2. p. 253. 1982.

Nakamura, Y.O. and T. Yasumoto. Occurrence of Saxitoxin in Puffer Fish. Toxicon, 22:3. pp. 381-385. 1984.

Nelson, J.S. Family Tetraodontidae-Puffers. Fish Base Online. 1994. URL: < http://www.fishbase.org/Summary/FamilySummary.php...>

Simon & Schuster. Simon & Schuster's Guide to Freshwater and Marine Aquarium Fishes. New York : Fireside Books, 1977.

Tomoko, Y. et al. Production of Tetrodotoxin and its Derivatives by Pseudomonas sp. Isolated from the Skin of a Pufferfish. Toxicon, 25:2. pp. 225-228. 1987.