Tetraodon suvattii, or the arrowhead puffer, is one of those fish you either take an instant like or dislike to. Their fry however are another story. Who can fail to see the beauty in such small delicate versions of their parents? Be warned though, as eventually they will grow into the mean and aggressive puffer we know as the arrowhead.
The suvattii is a freshwater puffer found in rivers from the Mekong basin of South-eastern Asia. It can be expected to reach around six inches of length at full maturity. The adult suvattii has a brown colouration to the top half of it’s body that starts to blend in to a mottled pattern as it reaches the lighter beige colour of its underside. The only other real marking it will have is a very distinctive darker patch on its head in the shape of an arrowhead, hence the common name arrowhead puffer. Suvattii usually spend most of their time camouflaged on the river bottom waiting for their next meal to pass over the top of them. These are ‘lurker’ puffers similar in appearance to the African puffer, the Tetraodon miurus. Both species are known to bury themselves with just their eyes protruding. With their upturned mouth they can strike from their buried hiding place and attack from beneath.
In the aquarium, as with all puffers I have noted the vast differences in personalities. Originally my set up included three suvattii puffers and I provided ample space for them. Plenty of overhangs, caves and a heavily planted/decorated tank is essential when keeping puffers together. The more space, and the more the lines of sight that are broken up, the more chance you will have of keeping a male and female of this species together. Finding a pair could prove to be difficult as the suvattii exhibit no external distinguishing features to identify their sex. Plenty of space is a must as with all puffers but generally 25 UK gallons should be allowed per suvattii. Put these factors in place and it will help increase your chances of keeping these puffers together by keeping the aggression between them as low as possible.
It is as puffers mature that we will witness aggression. This happened as one of my suvattii reached maturity. Despite replicating the factors already mentioned, the bigger, more dominant suvattii became too aggressive taking it’s aggression out on the other two. He created havoc throughout the tank and had to be re homed.
Last summer I noticed a small amount of courtship between the remaining two and realized I must now have a male and female. Despite this, nothing developed. This summer however, courtship increased somewhat with the introduction of a flat piece of slate to the aquarium. This was simply placed on top of the substrate in a visible position that had overhangs from Java Fern to provide some cover. It is believed that the suvattii dig pits in the substrate inside their cave in which they will lay their eggs and although I often watched them do this, I never saw any eggs.
Their behaviour after the addition of the slate came as a big surprise to me and I witnessed courtship increase. It is usually the male that initiates the courtship by cleaning the slate. First he would gulp in water to blow and force it onto the area to be cleaned. This would be followed by him swimming over the area, rubbing his underside against the slate. Once this was complete, usually the day later, the female would join him over the area he has marked. The two puffers would then start by circling each other. The male will semi-inflate itself and take the slightly higher circle around the lower female. Both the male and female will continue to circle each other nose to tail with occasionally the male butting the underside of the female. Gradually the circling will lower in height until the female is a fraction above the area where she will deposit the eggs. It is at this stage that the female will completely change colour from the dark brown colouration described before and adopt a much lighter gray colour. Remember the darker arrow patch? Well this arrow will now become almost white in colour and be a lot lighter than the rest of the body.
The male at this point is still above the female but will adopt a vertical position now with his nose pointing downwards. Occasionally he will inflate and deflate forcing water underneath the female, which in turn will lift her up off the bottom. This courtship can last anything from a few hours to several days. I have also witnessed some ‘false runs’ which will end up with both puffers going their separate ways.
When the female is ready to lay, she will swim up and down the area to deposit the eggs watched very closely by the male. He will continually blow water onto the area. Although the eggs that are laid will adhere to the surface they are laid on, occasionally the force of the male ‘blowing’ will scatter some of the eggs. The scattered eggs are left and are not replaced by either puffer.
Once the female has laid, she will simply swim off leaving the male to swim over the eggs to fertilize them. This is done very quickly and then he will then stay with the eggs until they hatch. His job now is to hover a fraction above them constantly fanning them with his fins, protecting them from predators. The male at this point will become extremely aggressive as he takes on the role of guardian. He will often attack anything within range of ‘his’ eggs. This unfortunately will include the female and often she will need to find somewhere to hide and stay well out of sight of the male. It is essential that space is given and the lines of sight are broken up for the protection of the female. If this is not possible then I would highly recommend removing the female temporarily. The courtship usually happens late summer towards the end of August. I cannot comment on water conditions triggering the events as parameters are very consistent with 50% weekly water changes.
The eggs are laid in very neat clusters and are transparent. They are between 1-2mm in diameter and hatch around day 6-7. After 4 days the fry can actually be seen inside the eggs, and on closer inspection their eyes can be seen to move. Closer to the hatching stage, the eggs turn to a brown colour. The critical stage, as with any egg laying species, is as they hatch, for it is now the fry become vulnerable. I found the hardest part in raising the fry is providing enough food for them. This is probably why people have failed in the past. Initially I left the first batch in with the parents but issues arose with them finding the food and avoiding the filter! The second batch I removed to a fry rearing tank, which had been supplied with Liquifry No1 in plenty of time to allow it to establish. The eggs hatched with the aid of an air stone to simulate the fanning by the male. The fry had a smaller tank now with a more readily available and easier to find food source. For the first day or two they will survive on their ‘yolk sacs’ but once that has depleted then they will have to search for food in order to survive. Some will find this very hard, especially the weaker ones. The more readily available the food source, the easier they will be able to find it.
As the suvattii fry are so small, another problem with feeding will be encountered. I had extreme difficulty in telling whether they were actually feeding or not to start with. Initially I just had to hope that they were finding the food themselves. The supply of food after a few days was replaced with baby brine shrimp, both frozen and live. Initially there was a problem of supplying enough live baby brine shrimp so I had to supplement with frozen. This, I am glad to say was readily accepted. Again the air stone helped increase the water agitation and gave the appearance of the frozen food being alive. Suvattii fry in the wild will only take live food, so simulating frozen food to be live helped a great deal. The feeding schedule I adopted initially I found was not enough. I had to increase the frequency of feeds, firstly from three to four a day, and then to five. The fry will readily accept any amount of food available to them and I thoroughly recommend over feeding, ensuring they all get their fill. It is relatively easy to see the golden glow of the baby brine shrimp in their bulging stomachs, so it is fairly easy to tell which are feeding well. As I am over feeding I will always clean the uneaten food from the bottom of the tank after each meal.
The fry rearing tank is a simple bare bottomed tank with an air powered sponge filter, heater, and a clump of Java fern. I noticed that the fry in the bigger tank spent most of their time hiding and resting on the leaves of the java. The bare bottom tank made maintenance easier and the tank had 70% water changes daily. The fry themselves despite their tiny size are extremely quick movers. Although they spend the majority of their time camouflaged on the bottom or resting in the leaves, I believe their initial burst of speed they can exhibit will be enough to out pace most predators. This burst of speed will at least see them out of harms way to the cover of the plants. They are extremely inquisitive, unlike their parents as they will often swim towards you when you approach the tank. The adults only show interest at feeding time. From the hideout they will rush towards the surface and hastily consume large quantities of food and then retreat just as quick. The fry however, will actively seek their food which in the wild they would have to do in order to survive.
From the moment they are visible inside the egg they immediately take on the characteristics of the suvattii. The colouration is there, as too is the unique suvattii shape. Even from day ten the identification is complete with the ‘arrow’ becoming visible on top of their heads. It is around day ten as well that a red ‘eye’ spot will appear towards the tail end of the fish. This is a typical characteristic of many puffers but not so the adult Tetraodon suvattii itself. It will be interesting to note at what stage this spot can no longer be seen.
As the fry grow they can be fed bigger live foods, including daphnia, brine shrimp and eventually when their size permits, bloodworm. Time will only tell if they do survive and grow to mature adults. I certainly hope so as there is little to no documentation on breeding this species. What little information is available can be found in the book entitled, The Puffers of Fresh and Brackish Waters (Ebert, 2001). Here he briefly explains the courtship and the fry themselves. With reference to the feeding of the fry, my experience has been somewhat different. Due to their size, it was not possible to feed them anything other than baby brine shrimp for up to the first three weeks. All appeared healthy enough but lacked the size to consume anything larger or more substantial.
Eventually as the fry grow there will be the need to separate them as these can be a very aggressive species of puffer who are known to fight amongst each other. Separation may need to be done sooner rather than later, as a bite when they are small can be lethal. Separating the puffers as they grow will also assist in feeding them. It can be assured then that they are all feeding and all receiving their fair share of the food.
Adapting them to ‘dead’ food is essential for the puffer in the aquarium. Once they are big enough it is a good idea to try to get them to readily accept mussel, krill, prawn, cockle etc. At first this might be difficult with the puffer ignoring the food and simulating live food again is the key to successful feeding. Tie a piece of mussel meat to a thread and dangle and bounce the food in front of the puffer. A piece on the end of a skewer is another idea to entice them to attack. Initially this is what they will do before they learn to accept the annoyance in front of them as food! Feeding frequency should also be reduced as the puffer grows, culminating in the adult only being fed once or twice weekly.
The T. suvattii along with other puffers are scale-less fish which makes them susceptible to infections and disease, which proves a major problem for the fry. This therefore means that you have to be on top of the water conditions and a bare bottomed tank will assist in cleaning and maintenance. Adult puffers are very hard to treat and medicate, so the chances of the fry surviving an infection are extremely slim.
Tetraodon suvattii fry are extremely difficult to raise. There are the initial problems of finding a male and female and then hoping they will firstly co habit, and then breed successfully. The supply of food is another problem to overcome as even baby brine shrimp at first are too big for them.
To date I have raise close to 200 specimens and have learnt new techniques that help mimic the male and so improve the quality of the hatching rate. My latest and biggest hatching numbered 60. The increased rate was brought about by actually helping the fry to hatch. I noticed that some became stuck to the slate and could not free themselves and so quickly died. Remembering that I witnessed the male blowing them from the slate as they hatched I simulated this by gently blowing water onto the hatching eggs to free them from the slate. This allowed them to be free and search for food.
Suvattii fry are fragile, unique and delicate creatures, a complete contrast as to what they will hopefully become as they grow.
Fry rearing tank statistics.
Size — 2.7g
Temperature — 26 C
pH — 7.6
GH — 10
KH — 8
70% daily water change with a clean up of uneaten food after each feed.