This care sheet is written with the aim of providing the optimal care for this species of fish.
Pufferfish Enthusiasts Worldwide endeavours to inspire and promote the highest standards of care - not basic or minimum care - using the best evidence available at the time.
The suvattii is a species of freshwater pufferfish belonging to the Pao genus.
The P.suvattii previously belonged to the Tetraodon and Monotrete genera until being reassigned in 2013 to Pao.
Common names for this species include Mekong Puffer, Pignosed Puffer, Hognosed Puffer and Arrowhead Puffer.
The specific name honours Chote Suvatti, ichthyologist and former professor of Kasetsart University who greatly contributed to the taxonomic work on fish in Thailand.
In the wild
The P.suvattii is believed to be endemic to the lower Mekong mainstream and its larger tributaries of Thailand and Laos.
It lurks within dense submerged vegetation and wallows in the muddy substrate of its suitable habitats, ready to launch a surprise attack on any prey items that swim within striking distance. It feeds on smaller species of fish, freshwater crustaceans and benthic animals such as worms.
The P.suvattii populations in the wild are still healthy in suitable habitats and it is considered 'Least Concern' by the International Union for Conservation of Nature (IUCN).
In the aquarium
The P.suvattii is a popular choice for ‘oddball’ enthusiasts and imports of wild-caught specimens are quite common.
This pufferfish requires highly oxygenated water with a medium to strong flow, but not overpowering.
A good strength of flow can be achieved with spray bars from a canister filter, angled towards the top of the water.
Powerheads with narrow gaps in the grill can also be used to create additional flow. We would advise that cages or guards (such as anemone guards) are used on powerheads to prevent entrapment/injury.
This species prefers a scape which includes an abundance of spaces in which it can hide, but the tank must also provided lots of areas of uncovered substrate to allow for wallowing (read substrate).
Water-logged driftwood and smooth boulders/rocks can be incorporated into the scape of the aquarium. Hardy epiphytes, such as Anubias and Java fern varieties, can be attached to the hardscape for decorative purposes and to provide additional areas of harbourage, but plants that need to be planted into the substrate should be avoided because the P.suvattii will disturb the roots.
Substrate
The P.suvattii is an ambush predator and will spend most of its time lurking in-between the aquarium decor and wallowing (buried) in the substrate.
This is how this species naturally hunts, awaiting any potential prey to come within striking distance. It is important that the Suvattii puffer is provided with a very soft, sand substrate for wallowing. A soft sand substrate should be considered an essential and not an optional extra.
The Suvattii is a wallowing species and should always be afforded the provision of a substrate which allows it to exhibit its natural behaviour.
The depth of the sand should always match the depth of the fish's body. It is recommended to start as shallow as possible and gradually increase the depth as the fish grows. This fish will disturb the substrate on a regular basis by moving from place to place within the sand, but it is recommended that the keeper regularly stirs up the substrate to stop the sand from ‘compacting’ and to prevent the build-up of anaerobic bacterial populations.
Gravel and plant soil/substrate is unsuitable for the Suvattii and may cause injury if the fish attempts to wallow in it. Any sharp/course pieces should be avoided/removed.
Tank Size
The tank should have a minimum footprint of approximately 80cm (31.5 inches) x 35cm (13.78 iches), with a height of 40cm (15.75 inches).
This translates to a tank volume of approximately 112 litres or 29.6 US gallons.
Water values
Maintain the following water parameters:
PH: 6.5 - 7.5 (in the middle is ideal)
Temp: 22-26°C (71.6 -78.8°F)
NH3/NH4+: 0ppm
N02: 0ppm
N03: below 15ppm *ideal
GH: 5-12 dGH
Tankmates
The P.suvattii is among one of the most aggressive pufferfish species. It will eat any fish that will fit into its mouth and will severely (often fatally) wound larger tank mates, so they should be kept as a solitary specimen.
The experienced aquarist may attempt to breed this species, but the behaviour between conspecifics is highly unpredictable.
Sexual dimorphism
There is no known method of determining the sex of this species for the home aquarist.
Notable behaviour
This species is known for its aggression and the aquarist must always exercise caution when their hands are in the aquarium. There have been many instances of these fish biting the preoccupied keeper during tank maintenance.
They are known to jump from the aquarium if startled, so they must only be housed in an tank with a tight-fitting lid.
Feeding
One of the most important elements of keeping the P.suvattii is to provide a varied and balanced diet, in order to ensure that their nutritional needs are being met.
The P.suvattii is primarily piscivorous (feeding on fish), but it also eats small crustaceans (small freshwater crabs and shrimp) and other benthic animals, such as worms, in the wild.
Our preferred foods for these fish include:
Thiaminase-free fish meat, cut into manageable chunks (read Feeding fish)
Gutloaded Earthworms
Gutloaded Cockroaches, crickets, locusts and woodlice
Repashy - Grub Pie
This species should not be offered cockles, mussels, clams, oysters or similar mollusks.
The teeth of the P.suvattii do not grow as quickly as some other species of freshwater pufferfish, so the need to feed hard food items is greatly reduced.
Feed a ratio of 40% fish and 60% insects and worms.
Owing to the inactive nature of this species, it does not require feeding daily. Three times a week is usually sufficient.
Feeding fish
Naturally, the P.suvattii preys upon a very wide selection of different species of fish in the wild. For this reason, we recommend alternating between as many different suitable options as possible.
Frozen Pond Smelt (Hypomesus olidus) are widely available and they are small enough for the P.suvattii to eat whole. Pond Smelt is a common choice of food and bait, so it can typically be purchased from all well-stocked aquatic stores and bait suppliers. Some species of smelt such as Rainbow Smelt (Osmerus mordax) contain thiaminase (read Thiaminase), so it is important to ensure that you know what species of smelt you're buying.
Generally, the choices of suitable fish at fish counters and markets are going to be quite limited, but there are several common options.
Larger species of freshwater fish such as Lake Trout (Salvelinus namaycush) and various Tilapia species are suitable, but these fish are obviously too big for the P.suvattii to eat whole so they need preparing and cutting into manageable chunks. Discard of the internal organs, head and fins, fillet the fish and cut the fish fillets (scales and skin attached) into chunks small enough for the P.suvattii to eat within one minute. These pieces can be frozen and kept for up to three months.
Insects and worms
Gut-loaded insects and earthworms are excellent sources of nutrition for this fish and are used to replicate the gut-content of the P.suvattii's natural prey.
They are also ideal substitutes for freshwater crustaceans and are arguably far more nutritious than the saltwater crustaceans that most aquarists will be limited to at a fish counter/market.
Thiaminase
Some fish and crustaceans contain thiaminase, which is an enzyme that renders thiamin (Vitamin B1) biologically inactive. This means that the pufferfish can not absorb any thiamin from that food.
Thiamin is a critical nutrient because it is an essential component of energy metabolism and it plays a key role in nerve, muscle, and internal organ function.
If a fish’s diet is mostly or completely made up of food items that contain thiaminase, that fish will develop a thiamin deficiency.
After consulting with veterinary professionals and other specialist keepers, we feel that avoiding foods that are known to contain thiaminase and replacing them with equally nutritious thiaminas-free food items is the safest, long-term option. This is the approach that we have taken with all of our pufferfish.
Feeder fish
We do not recommend the use of live feeder fish.
Feeder fish are often bred in squalid and overstocked conditions, where bacteria such as columnaris and mycobacteriums, and parasites such as Camallanus worms and Ichthyophthirius multifiliis (whitespot/ich) spread through the population very quickly.
Feeding feeder fish to your puffer greatly increases the chance of introducing pathogens to your aquarium, which can then infect your puffer and will require treatment. Feeder fish themselves are also usually nutritionally deficient.
Pao suvattii does not need live fish to thrive and will very often readily accept frozen-thawed food immediately after settling into the aquarium. The use of feeder fish can also cause piscivorous to become very finicky and they may start refusing anything but live fish.
This is another reason that we strongly encourage you to begin the weaning process (read below) immediately.
Tips on offering prepared foods / weaning
Although some specimens will be reluctant to eat frozen-thawed foods at first, they can learn to accept it. The best training exercise is to offer nothing but live-earthworms to begin with and when your puffer is readily accepting those, start offering the same earthworms on forceps, building an association between the forceps/you and food.
When your pufferfish is accepting earthworms without hesitation from the forceps, you can then begin to offer other things, such as cockroaches, other insects and pieces of frozen-thawed fish. After several weeks, you won't need the forceps and your fish should readily accept any suitable foods that you drop into the tank.
Filtration
This pufferfish is intolerant of poor water conditions, so a high level of biological and mechanical filtration is needed to deal with the amount of waste that this fish produces.
Adequate filtration combined with excellent husbandry is essential to the health of this species.
Frequent water changes must be carried out to maintain N03 (nitrate) levels below 15ppm.
Inflation
Pao suvattii can inflate themselves when frightened or stressed. They should never be provoked into inflating! It is not unusual for wild-caught specimens to inflate at their own reflection while they settle in to life in the aquarium. They will quickly realise that the fish they can see poses no threat.
When confronted by what it thinks is an intruder, the P.suvatti will begin to react by staring intensely. If this isn't sufficient in scaring the challenger away, the P.suvatti will lower its head and swim towards the fish in a threatening manner.
The P.suvatti will then open its mouth to display the teeth and swim around the fish. It will then inflate its body and swim towards the threat in an erratic pattern.
As a last resort, the P.suvattii will charge at the threat, with the intention of battle. If you see your P.suvattii challenging its own reflection, turn the lights off and allow the fish to settle.
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