By Heather Cooan

The Tetraodon suvatii, commonly sold in the aquarium trade as the arrowhead puffer, Mekong puffer, pig-nose puffer or hog-nose puffer, is one of the most vicious of all puffers. The suvatii is rapidly growing in popularity due to the observable butchery involved in its natural eating habits. However popular this fish may be, it is also highly misunderstood due to the scarcity of information available surrounding the entire Tetraodon species. The suvatii can be and often is a difficult fish to keep and for those unfamiliar with puffer fish in general it is not a good introductory choice.

The suvatii is an average sized fish that grows to a maximum of six inches at full maturity. This specimen is collected from rivers in the Mekong basin of Southeastern Asia, Thailand and Laos making this fish an exclusively freshwater species. The suvatii lives in freshwater rivers where there are often muddy and rocky substrates. The native riverine environment of this fish consists of clean, constantly moving, oxygenated water. The aquarist should do closely replicate these conditions in aquaria. This is best accomplished with a high level of aeration and filtration along with weekly 50% water changes. It is extremely important to keep optimum water conditions as this fish is a very messy eater and produces a large bio-load compared to its size. Doing weekly water changes at 50% along with weekly gravel cleaning, the parameters of the tank will remain consistent and eliminate any stress to the fish. Eliminating stress will increase immune function, decreasing the likelihood of contracting bacterial or parasitic disease. Water parameters should remain constant at readings of 0 ammonia, 0 nitrite and under 20ppm nitrate. The T. suvatii is a relatively long-lived and hardy fish, rarely developing bacterial or parasitic infection and wounds heal rather quickly. When instances that may require medical treatment arise, it is not permitted to treat this fish with copper-based medications. All puffers are extremely sensitive to medications as a whole and should be avoided if at all possible.

In the wild, the T. suvatii is a specialized hunter, feeding on other fish. The puffer is an extremely effective hunter, who uses the stealth method to surprise and catch its prey. Burrowing down into the substrate, the suvatii waits for his next meal to pass over its nose, at which time it leaps from the sand and devours the animal in one quick motion. Small fish are devoured immediately, with violent chewing movements in the whole. Larger prey fish are first killed, often times disemboweled or chewed in half and then gradually eaten. The suvatii is almost always successful in their hunting strategy and their strong teeth optimize their attack.

In aquaria however, the T. suvatii must be trained to accept frozen foods, as it's main staple. This is necessary due to the increasingly poor conditions most fish are kept in at many local fish stores. These conditions are consistently worse for "feeder fish" and can be detrimental to the puffer when feeding from these fish. The conditions in which feeder fish are predominantly kept are such that parasites and bacteria are abundantly present. The T. suvatii, along with all other puffer fish, are scale less and without gill covers, making them a prime target for parasitic and bacterial infection. Due to the possible illnesses resulting in the feeding of fish to the suvatii, it is essential to quarantine any and all fish that will become a meal to the puffer. The quarantine period should last for at least a week, with any medications or treatments performed during this period, to ensure proper health and quality of the live food. Feeder fish should not be a staple diet for the T. suvatii but may be given as a treat on occasion, and only after a proper quarantine period.

It may be difficult to train the T. suvatii to take frozen or "dead" foods, but it is crucial to the health of the specimen that its owner do so. Tying a piece of thread around a fat juicy shrimp and lightly bouncing the shrimp close to the snout of the fish, capturing the suvatti's attention with movement of the food, is a great way to achieve this. Other methods of training include the use of tongs or forceps to gently wave the piece of food close to the fish's mouth. Depending on the temperament of the specimen it may be enough movement to capture its interest by simply adding the food to the current of the filter inside the tank.

During feeding time, the puffer will shoot to the surface and hastily guzzle down large amounts of food, usually causing the fish to double its size. Due to these large feedings, this fish should not be fed every day. The feeding structure of this fish should consist of feedings every other day, while the specimen is less than four inches in size and once a week at four-six inches. During these feedings, the suvatii should receive any of the following foods, krill, shell on shrimp, crab legs, crayfish, live or frozen mussels, live or frozen clams, live crabs, live ghost shrimp.

When feeding ghost shrimp it is important to gut load them first. Ghost shrimp are not of great nutritional value and by gut loading them important nutrients are added to the benefit of the puffer. Gut loading consists of feeding the ghost shrimp a healthy dose of nutritional foods before feeding the shrimp to the puffer. Foods that are good for this are flake, crab pellets, algae wafers, and many other foods of high nutritional value.

Foods that are unusually high in protein or not related to foods that the puffer eats in the wild are not permitted. Foods such as beef heart, red meat and chicken may contribute to the development of a fatty liver or cirrhosis of the liver, which will essentially kill the fish over time.

Due to their specialized nature as piscivores, this fish should not be kept with any other fish, as the suvatii will not hesitate to make a meal of the fish. When the T. suvatii is presented with an intruder to their territory, it reacts immediately with great persistence, first staring intently at the intruder. When the confrontation ensues in open waters, the suvatii charges the intruder with a threateningly lowered head. The suvatii then opens its mouth and swims slowly towards the intruder. In many cases this behavior is sufficient enough for the offending fish to leave. When the offending fish does not leave after this display, the T. suvatii positions its broadside toward the offending fish and inflates its body. Menacingly, the inflated puffer then swims in a zigzag pattern in front of the offending fish. The head is lowered and the suvatti's mouth open with the strong sharp teeth displayed. After the display of inflation and warning, the puffer will attack to afflict the offending fish with serious wounds.

It is however, possible to successfully keep conspecifics and similar with this puffer and to successfully breed them. The meeting of conspecifics results in a display of both fish horizontally flattening themselves out and inflating while lowering their heads toward each other while they slowly swim in a circle around each other after which they retreat to their own territories with no damage to either fish. A large, heavily decorated tank with plenty of broken lines of sight and multiple territories helps to keep aggression between tank mates to a minimum. The T. suvatii has been successfully bred in captivity as far back as 1973 by Patrik Recher and is recorded as the first of the Tetraodon species to spawn in aquaria. Although spawning has been observed, there is no recorded evidence of sexually dimorphic characteristics in this fish. The spawning takes place after a courtship in which the male and female perform a dance together. The male fans the eggs while waiting for them to hatch.

The temperament of the T. suvatii in aquaria is commonly quite pleasant toward its owner. This usually inactive fish will quickly swim to the glass to great its owner and beg for food, thrashing around at the surface. While performing tank maintenance, the aquarist should be mindful of his/her fingers, as they resemble the movement of a potential meal to the suvatii. It may be necessary to capture the suvatii in a net while performing any maintenance so as to prevent injury to the aquarist.

The Tetraodon Suvatii is a distinctively appealing fish for the experienced aquarist, who respects its natural power and peculiarity. Hobbyists will be delighted to keep such a maliciously miraculous specimen.