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spot-fin porcupinefish

✓ Diodon hystrix
  • Diodon histrix
Diodon histrix
  • Diodon histrix
Family Diodontidae
Genus Diodon
IUCN category (World) LC
Diodon hystrix Diodon hystrix
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Introduction

Descriptor : Linnaeus, 1758

Diodon hystrix, commonly known as spot-fin porcupinefish, is a marine species belonging to the order of tetraodontiformes. Its distribution is circumtropical, extending to all warm seas globally, with the notable exception of the Persian Gulf where it is absent.


In the Indo-Pacific ocean, it inhabits the Red Sea, East African coasts, Madagascar, India, Sri Lanka, as well as most archipelagos up to Japan, Hawaii, and New Zealand. In the Atlantic, it is found from New England (USA) and Bermuda to Brazil, including the Gulf of Mexico and the Caribbean Sea.


Although considered common globally, its local abundance varies significantly: it is rare in some areas like the Bismarck Sea, the Gulf of Thailand, or off the coast of Florida, while it is one of the three major pufferfish species on the coasts of India.

Who is it?

Morphology

  • Type
    pufferfish
  • Average size
    50 cm
  • Maximum size
    90 cm
  • Shape
    Balloon and near
  • Pattern
    circle pattern
  • Type
    pufferfish
  • Average size
    50 cm
  • Maximum size
    90 cm
  • Shape
    Balloon and near
  • Pattern
    circle pattern

How to recognize This fish ?

This species belongs to the group of pufferfish. These fish are nicknamed like this because they have the ability to inflate themselves when they feel threatened.

To achieve this inflation, they swallow water and fill their stomach to more than double their volume. This is made possible by their stretchy skin. This subterfuge makes them look much more impressive to their predators. They are also much more complicated to swallow. This change in shape becomes a disadvantage for these fish that, once inflated, can hardly move.

The silhouette of Diodon hystrix is robust and short, characteristic of diodontids. Its body is covered with long sharp spines, folded backwards when the animal is not inflated, but standing vertically in case of danger when the fish fills with water or air.

The dorsal coloration ranges from gray-brown to beige, dotted with numerous small circular black spots, without large dark marks. The belly is white, often surrounded by a dark ring. The fins are speckled like the back. A row of about 16 to 20 spines is visible between the snout and the dorsal fin. The maximum observed size reaches 91 cm, although the average length is around 40 cm, with a maximum recorded weight of 2.8 kg.

Sexual dimorphism

No external sexual dimorphism is visible in this species. Males and females share the same coloration, size, and spiny morphology. Sex distinction is only possible by internal examination or during specific reproductive behaviors.

Behaviour & Life cycle

  • diet
    omnivorous with carnivorous tendency
  • Sociability
    solitary
  • territorial
    No
  • Way of living
    nocturnal

Tetrodotoxin or TTX is a neurotoxin produced by bacteria. In this species, it is present in large quantities in the liver, viscera and gonads but is also found in the skin.

Females are more toxic than males, this is due to the high concentration of TTX in the ovaries.

When poisoned, TTX is fatal in more than 50% of cases. This neurotoxin acts on the pores of the sodium channels, which stops the passage of nerve impulses, resulting in partial or total paralysis. Death is most often due to respiratory paralysis triggering cardiac arrest by collapse.

The behavior of Diodon hystrix changes during its growth. Juveniles, up to about 20 cm, lead a pelagic life in open water. As adults, the species becomes benthic, solitary, and strictly nocturnal.

During the day, it hides in caves, crevices, or reef holes, remaining immobile and sheltered. At nightfall, it emerges to actively hunt on the reef. Its diet is specialized in hard-shelled invertebrates such as sea urchins, gastropods, and hermit crabs, which it crushes with its powerful beak-shaped fused teeth. This nocturnal predation behavior makes it an important regulator of sea urchin populations on coral reefs.

Reproduction

  • Reproduction
    ovipare qui pond sur substrat découvert

Diodon hystrix is oviparous. The eggs and larvae are pelagic, drifting with ocean currents during the juvenile phase before metamorphosing and joining reef habitats to adopt the benthic lifestyle. The species can live up to a decade in captivity.

Harmless species

The species poses a potential risk to humans if consumed, due to the possible presence of toxins (tetrodotoxin) in its tissues, although this is not systematically confirmed for all populations. Handled with caution, it does not pose direct danger due to its spines, except in cases of defensive inflation where the spines can cause mechanical injuries.

Origin and distribution

Natural range
Invasive range
Mixed / unknown area

Geographic distribution & Conservation

Although common, the species is subject to local fishing for human consumption in some regions like Hawaii and Tahiti, despite reports of potential human toxicity that require confirmation. It is also dried and sold as a souvenir in various parts of its distribution range. There is an aquarium trade, especially in Brazil and Hawaii, although it represents a minor part of the global marine fish market.

Conservation status of populations (IUCN)

World : LC
France : LC

Where to see this species?

Aquarium des Lagons

What is its habitat?

Natural environment characteristics

  • Temperature
    25 - 30 °C
  • Depth
    3 - 20 m
  • Flow
    Medium and Slow

Biotope presentation

Diodon hystrix inhabits the coral reefs of lagoons and outer slopes, in subtropical and tropical waters. Its bathymetric distribution ranges from 2 to 50 meters deep, but the species is most often observed between 3 and 20 meters. Juveniles sometimes frequent mangrove habitats, such as in Mexico and Panama, before migrating to reefs.

The species is absent from the Persian Gulf, likely due to specific environmental conditions. This fish resides in structured reef environments, favoring areas with numerous hiding spots like caves and rocky overhangs. It tolerates a wide range of temperatures due to its circumtropical distribution, but remains dependent on clear and warm waters of coral reefs. The presence of hard-shelled prey, particularly sea urchin populations, is a determining factor for the quality of its habitat.

Species of the same biotope

Main recommendations for fishkeeping

Deontology

In order to preserve wildlife, if you acquire this animal, it must not be released into the wild. See also, the Fishipedia charter.

Fishipedia supports the practice of responsible and environmentally friendly aquarium keeping. We encourage maintenance if it is motivated by a desire to understand the biological functioning of living things and if it is done with respect for animal life.

We believe that aquaristics is an opening to the discovery of aquatic environments, especially freshwater, and that this knowledge is necessary to better protect and respect these environments. Logically, we refute the compulsive purchase of animals that would not find a sufficient and / or adapted place in the host aquarium.

Our recommendations

  • Min volume
    3000 liters
  • Population min
    1
  • Temperature
    25 - 30 °C
  • pH (acidity)
    8.2 - 8.4

Characteristics

  • Difficulty breeding
    moderate
  • Robustness
    tolerant
  • Behaviour
    peaceful

General reminders

It is strongly advised to read the complete dedicated file and to get information on the feedbacks of maintenance of the envisaged animal, this to avoid any potential conflict whose end result is generally the death of the individual (or the other inhabitants). It is important not to overload your aquarium to limit pollution. This will make maintenance easier.

The realization of a seawater aquarium requires certain knowledge beforehand. Seawater is generally synthetic, consisting of reverse osmosis water and synthetic salt at a level of 33g / liters. It is also possible to take seawater directly (after making sure that the water is not polluted). The operation of a seawater aquarium is done in three phases: the installation of a living stone decoration, the introduction of invertebrates one month later, and the introduction of fish 3 months later. It is essential to wait as long as possible before to introduce the animals so that the micro-fauna has had time to develop well. The balance and the physico-chemical stability are fundamental for the success of this type of tank.

General reminder on maintenance datas

Le démarrage d'un aquarium est une partie primordiale pour l'équilibre et le bien-être des poissons. Lorsque l'on met en eau un aquarium, l'eau passe naturellement par un cycle biologique : le cycle de l'azote. Celui-ci dure environ trois semaines. Tous les 2 jours, nous vous conseillons de tester votre eau jusqu'à ce que le taux de nitrite soit à zéro pendant plusieurs jours d'affilée.

Pour accélérer ce cycle, vous pouvez utiliser un activateur de bactéries comme JBL Denitrol. Cette solution riche en bactéries vivantes et enzymes permet une mise en place rapide du cycle de l'azote. Les poissons peuvent alors être introduits plus rapidement.

Il est important de tester l'eau de son aquarium régulièrement pour maintenir un environnement sain pour les poissons et les autres habitants. Les tests d'eau permettent de mesurer les niveaux de différents paramètres tels que le pH, la dureté totale, ainsi que les taux de nitrates, de nitrites et d'ammoniaque.

Pour réaliser ces tests, vous pouvez utiliser des produits d'analyse spécialisés tels que JBL ProScan qui permet de réaliser un diagnostic de l'eau directement via un smartphone. Il existe également des coffrets de tests plus classiques de bandelettes, comme JBL PROAQUATEST.

En cas d’usage de l’eau du robinet, vous pouvez utiliser un conditionneur d’eau de type Biotopol de JBL pour éliminer les substances nocives comme le chlore, le cuivre, le plomb et le zinc. Une eau trop dure ou trop calcaire peut être inadaptée à de nombreuses espèces tropicales d’eau douce. Si nécessaire, vous pouvez la couper avec de l’eau osmosée ou de pluie filtrée afin d’obtenir une dureté plus adaptée aux besoins de vos poissons et de vos plantes. Les conditionneurs d'eau garantissent une meilleure santé aux poissons et une meilleure croissance des plantes.

Chlorine and chloramine are dangerous for the health of animals. Used to disinfect water, these agents are present in significant quantities in tap water. We recommend using an anti-chlorine agent every time you change the water. In addition to chlorine, treatments and medicines sold for aquarium use sometimes contain dangerous heavy metals in high doses.

Specific needs for the spot-fin porcupinefish

The spot-fin porcupinefish is a marine species which lives naturally at a temperature between 25 °C and 30 °C. Nitrate levels should remain below 50mg/L. To keep the water clean and unpolluted, plan on changing 20% to 30% of the water volume each month. In seawater, it is also possible to remove nitrates using one of the following methods: Jaubert, denitrator on sulfur, biopeletts, vodka method.

The breeding of this species is accessible on condition of being well informed about its needs in aquarium . Any cohabitants must be chosen with care to avoid the loss of animals.

Formal incompatibilities

Be careful, the spot-fin porcupinefish is incompatible with molluscs, crustacean and corals.

Cohabitation & Environment

In a community aquarium context, this species should be kept in a minimum volume of 3000 liters.

The spot-fin porcupinefish is a peaceful species that generally does not exhibit behavioral problems in a community aquarium.

Tips for feeding

The spot-fin porcupinefish is omnivorous with carnivorous tendency.

This species can eat dry food (flakes, pellets), fresh food and frozen food. To avoid deficiencies, it is recommended to vary the types of food.

Feed animals in moderation to maintain good water quality. Meals should be eaten within 2–3 minutes, served in several small portions rather than a single large ration.

Uneaten food quickly decomposes, releasing ammonia, nitrites, and nitrates, which disturb the aquarium’s biological balance.

Make sure each species can access food properly, slower or bottom-dwelling individuals may require targeted feeding.

Reproduction protocol

  • egg-laying protection
    Yes

Hybridization risks

In general, it is advised not to mix several species of the same genus or different varieties of the same species, to avoid the risks of hybridization.

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To go further

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Sources & Contributions

Participation & Validation

The Fishipedia team and specialist contributors are committed to providing high-quality content. However, although the information comes from scientific sources or testimonials from specialists, the cards may contain inaccuracies.

Benoit Chartrer

Benoit Chartrer

Patrick Chartrer

Patrick Chartrer

Translation

Translation done with the valuable contribution of our translators, who make this information available to a wider audience. We sincerely thank them for their commitment.

Benoit Chartrer

Benoit Chartrer

Bibliographic references

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