Pao suvattii – Arrowhead Puffer
Pao suvattii was first described by Sontirat & Soonthornsatit in 1985. They are commonly called Arrowhead Puffer, Hognose or Pignose Puffer.
The genus name, Pao, comes from the Thai and Lao words for puffer fish:’pla pao’ and ‘pa pao’. ‘Pla’ and ‘pa’ mean ‘fish’, and’pao’ means ‘purse’ or’bag’, referring to the round body shape. The species name, suvattii, honors Thai ichthyologist Dr. Chote Suvatti, who contributed much to the knowledge of Thai fish.
The Pao suvattii belongs to the family Tetraodontidae, puffer fish, and the genus Pao. This species was previously classified in the genus Tetraodon, but after further research, this classification was modified.
Valid scientific synonyms for Pao suvattii are Tetraodon suvattii and Monotrete suvattii.
Description of the Pao suvattii
Pao suvattii has a flattened body with a prominent, upward-curving mouth (a “pig nose” appearance) and thick lips. The head is flattened and tapers into a long snout. The basic color is grayish to brownish. Small, dark spots can be seen on the back, while the flanks show dark ocelli (eye spots) with whitish dots, especially in the rear part of the body. A prominent feature is a more or less complete eye patch on the back of the body, which may be in the shape of a V. The cheeks and underside of the head show a series of oblique stripes. The fish grows to a total length of about 12 to 15 centimeters. The color can vary depending on the environment; on lighter surfaces, the color fades.
The fish owes its name Arrowhead Puffer to the black arrow shape on its back.
Gender and Age Differences
The available information gives no clear indication of physical differences between males and females Pao suvattii. Behavioral differences are, however, observable during reproduction; the male guards the eggs and shows aggressive behavior when disturbed. A notable difference is that a female can spawn solo (solo spawning), which is not common in fishes. No information is available on differences between juveniles and adults.
Behavior and Temperament
The Pao suvattii is an ambush predator (sit-and-wait predator) that hides in dense underwater vegetation and digs in the muddy bottom. They are not very active, but move quickly toward their prey as soon as it comes into view. In captivity, they are territorial and may exhibit aggressive behavior toward conspecifics. They live solitary, unless it is mating season. They are bottom dwellers. They can inflate their bodies if they feel threatened.
Defense mechanisms
The Pao suvattii possesses two main defense mechanisms: inflation and tetrodotoxin. When threatened, the fish can rapidly inflate its body with water, making it significantly larger and less attractive to predators. This is an effective deterrent, but it is an energy-intensive process and frequent inflation can stress the fish.
In addition, the skin, organs and teeth of the Pao suvattii contain tetrodotoxin, a potent neurotoxin. This toxin makes the fish unsuitable as food for most predators. However, it is important to emphasize that although the fish contains tetrodotoxin, it is generally harmless to humans unless provoked or consumed. Touching the fish is not dangerous, but it is crucial to avoid biting the fish or consuming its innards.
The main advantage of these defense mechanisms is protection against predation, but the disadvantage is the energy cost of inflation and the risk of human exposure to tetrodotoxin if handled carelessly.
Pao suvattii biotope
Pao suvattii is native to Thailand and Laos, and recently the species was also officially recorded for the first time in Cambodia in the Ou Nampha stream, a tributary of the Sekong River in the northeastern part of the country. The species is mainly found in the lower part of the Mekong Basin. They are river fish that live in the slow-flowing parts of rivers, especially in the floodplains and stagnant pools of the Mekong Basin, including the Sekong River.
Their natural habitat is characterized by dense underwater vegetation and a muddy or rocky bottom. The water is clear to dark, depending on the environment and amount of sediment. Flow is slow to stagnant, depending on the specific location within the watershed. The banks of the water may be overgrown with a flooded forest . The bottom consists of mud or rocks.
Diet
Diet in the Wild: In their natural habitat in the Mekong Basin, the Pao suvattii feeds mainly on smaller fish species, freshwater crayfish and benthic animals such as worms. They are raid hunters (sit-and-wait predators) who hide in dense vegetation and wait for their prey. They hunt mainly on the ground.
Nutrition in the Aquarium: In aquariums, it is important to provide Pao suvattii with a varied diet that approximates their natural diet as much as possible. Suitable foods include: thiamine-free fish (cut into pieces), gut-loaded (nutrient-enriched) earthworms, crickets, grasshoppers, and wood lice. Frozen foods such as smelt (Hypomesus olidus) are also suitable, provided they are offered in small pieces that are manageable for the fish. It is important to avoid giving the fish too many high-fat foods, such as red meat or chicken, as this can lead to fatty liver, which is usually fatal . The Pao suvattii has a tendency to overeat, so it is recommended to feed them every other day. Mollusks such as clams and mussels are not suitable. A good ratio is about 40% fish and 60% insects and worms.
It is important to give them food with a hard shell such as crab, shrimp, snails etc. This will wear down their teeth and keep them from getting too long.
This species prefers live food. Some specimens do not eat dead food. You can try to slowly accustom them to dead food by feeding them with long tongs. Then hold some food with tongs. Hold this close to them and then move the food back and forth a bit until they pick it up.
The Pao suvattii Aquarium
To keep one Pao suvattii, an aquarium with a minimum bottom area of about 80 cm x 35 cm and a height of 40 cm (about 112 liters) is recommended. Keeping multiple specimens together is strongly discouraged, as this species is very territorial and aggressive towards conspecifics. Keeping multiple specimens is recommended only for experienced breeders who want to breed this species, but even then the behavior is unpredictable. It is a true freshwater species. Therefore, they do not need salt in the water.
Aquarium design should provide plenty of hiding places, such as dense areas of plants, water-saturated driftwood and smooth rocks. An open swimming area is not essential, but it is desirable. It is crucial to use a very soft, sandy substrate, as Pao suvattii likes to dig into the bottom (wallowing). The depth of the sand should be equal to the body depth of the fish, starting with as shallow a layer as possible and gradually deepening as the fish grows. Gravel or other sharp materials are inappropriate and may cause injury. Plants to be planted in the soil are not recommended because the fish will disturb the roots.
A strong current is desirable, but should not overwhelm the fish; this can be achieved with spray bars from a potfilter directed at the water’s surface. Avoid powerheads without protection to avoid clogging or injury. Lighting may be dimmed to mimic turbid water conditions in their natural habitat.
This species thrives best at a temperature between 22 and 26°C, a pH of 6.5 to 7.5 (ideally in the middle ) and an average GH of 5-12 dGH. Water quality should be optimal, with weekly water changes of 50% , good water movement and absolutely no ammonia or nitrite, and minimal nitrate levels.
The Pao suvattii should be kept solitary; it is not a suitable species to combine with other fish due to its aggressive behavior and tendency to eat smaller fish.
Breeding Pao suvattii
Not much is known about the successful breeding of Pao suvattii. Only one case is known in which a solo female deposited eggs. She was kept in a 12 gallon aquarium. There was an air pump with 3-5 puffs of air and a filter for sufficient oxygen. The temperature was around 26-27°C. This particular case involved a single female that was alone in the aquarium and laid eggs spontaneously (solo spawning). She was fed a diet of frozen shrimp (with shell), pieces of fish and shellfish.
The female made a pit in the fine sand substrate to deposit the eggs in. The deposition took place in the evening. The eggs were laid open and exposed in the pit. There were about 60 eggs in the first deposit, and about 30 in the second. The eggs were unfertilized in both cases.
Conclusion
Pao suvattii is a fascinating, but challenging fish species for advanced aquarists. Its aggressive nature and the need for specific setup and diet make it unsuitable for beginners. Solitary keeping is essential, and a carefully formulated diet, free of thiaminase, is crucial to his health. The observation of solo spawning in a female is a remarkable peculiarity, which deserves further investigation.
Despite the challenges, keeping a Pao suvattii can be a rewarding experience for experienced enthusiasts. The combination of its unique appearance, intriguing behavior and the need for specialized care makes this fish a special addition to an aquarium. However, further studies on its breeding and behavior are needed to determine the optimal conditions for this species.
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Author
Since I bought my first second-hand aquarium when I was twelve, I have always had one or more aquariums. I even converted a garage into a breeding room where I had 50 aquariums containing around 10,000 liters of water. At the moment, I have two aquariums: a 1,250-liter Tanganyika aquarium and a 250-liter community aquarium with plants. For the past 10 years, I have been working on this website as a writer and photographer.
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