Arothron nigropunctatus – Blackspotted Puffer
Arothron nigropunctatus comes in two different colour variants. The first variant has a beige ground colour with dark black spots. This is obviously why they are called Blackspotted Puffer. The second variant was previously called Arothron citronellus, but after research, it appears to be the same species and they have been synonymised as Arothron nigropunctatus. The second variant has a beautiful yellow colour. The lemon colour gave it its former scientific name Arothron citronellus. The genus name Arothron literally means nostrils.
Arothron nigropunctatus has a round body that tapers towards the tail. In nature, this fish can reach a length of 36 centimetres, while in a spacious aquarium it will not grow much larger than 25 centimetres. It has two large fins to the side and two slightly smaller fins above and below its body. The fins, which are all soft, serve for locomotion and are controlled by the pectoral muscle. The tail, which is long and rounded, serves as a rudder. The very hard skin is free of scales.
The pigmentation of the fish changes with age. When young, the fish is light yellow to light brown with many small, scattered dark spots and a black spot on the back. The older the fish gets, the fewer spots and the brighter the lemon yellow colour will become. The skin is covered with a very thick mucus and the opening of the gill cover is small.
In addition to the yellow colour, their four teeth are also very striking. This is a trait belonging to the Tetraodontidae (four-toothed) family, to which Arothron nigropunctatus belongs. The teeth are reminiscent of a beak and are fixed in the centre of each jaw. They consist of two large upper parts and two small ones on the lower jaw. They grow back as they wear. This “beak” is characteristic of eaters of crustaceans and relatively strong prey. The teeth remain visible even when the mouth is closed.
Another characteristic that belongs to these fish is the stomach sac that can store water or air and occasionally cause a large swelling of the fish.
The Yellow Puffer is found on many coasts of the Pacific Ocean. Sometimes you can see them swimming in open waters but they prefer to stay close to the reefs where they have hiding places.
It is a somewhat shy fish that immediately dives away at the slightest danger, but on the other hand, it is also very curious, sometimes costing them their life. Especially when they come too close to the coast and young inhabitants of those countries use this fish as a football. The water they live in is clear with a strong swell.
The aquarium intended for Arothron nigropunctatus should be quite spacious, i.e. with a capacity of about 300 litres. If we choose to keep it in the company of other fish species, it would be desirable to increase the capacity of the tank depending on the number and species. For decoration or back wall, care should be taken that the surface of the decoration is well finished and sanded. This can prevent the fish from peeling and swallowing fragments of indigestible and hazardous materials.
The decoration can be supplemented with skeletons of branched corals, such as: Acropora palmata, A.nobilis, A.arcuata, Millepora alcicornis, porite porites, etc.
The SG of the water should be between 1.020 and 1.025. The temperature in the natural environment is between 27 and 28 °C. In an aquarium, we recommend keeping it around 24°C. This difference makes it possible to apply in the following theory: temperature below the ecological data slows down the metabolism of the fish, reduces appetite, thus also the amount of waste, which results in a slowing down of water pollution.
Maintenance will mainly consist of mixing water (turbulence and oxygenation) and its partial and frequent changes, which is the only effective method of eliminating nitrates. The fish, if done enough partial water changes, will suffer little from disease.
The tank lighting should be on for about 12 hours a day, alternating, if possible, with switching off and progressive lighting of the light.
We know that Arothron nigropunctatus “pecks” the skeletons of madrepores and other substrates. Probably to feed on small crustaceans and gastropods that live there. These hard prey offer the fish two advantages: they are not fast, so easy to catch and their very strong structures allow the fish to “use” its teeth.
In the aquarium, the food can consist of shrimps (live or frozen, alternating with squid meat (Sepia). This restriction is practical and hygienic. It is indeed desirable to choose foods that are solid and protein-rich and that do not pollute the water by disintegrating We must also provide these fish with dead coral branches. This allows the fish to “use its teeth”. If we do not do this, there is a risk that they will search and nibble at the decoration. Equipment submerged in the aquarium is not safe.
Finally, it is important to know that the Arothron nigropunctatus is a voracious fish that must be fed several times a day in small amounts. In general, this fish pushes itself to the fore when food is provided. It is therefore wise to feed the fish in several places in the aquarium at the same time. Feeding little, but often, is a rule that should apply more than ever to this greedy fish.
Finally, a note in the field of toxicology. While we don’t intend to eat our Arothron, we should be aware that as they get older, they also become more toxic. The poison secreted by certain organs (sexual glands, gallbladder and digestive tract) is called Tetrodoxin. This toxin is very dangerous for people (or animals) who ingest the organs of these fish.
The Arothron nigropunctatus can live to be about 8 years old and sometimes longer in large aquariums where favourable conditions prevail.
Margie van der Heijden – Ons Natuurgenot Gouda