''Diodon eydouxii'', commonly known as the pelagic porcupinefish, is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

porcupinefish Porcupinefish are medium-to-large fish belonging to the family Diodontidae from the order Tetraodontiformes which are also commonly called blowfish and, sometimes, balloonfish and globefish. The family includes about 18 species. They are sometime ...

with a

circumtropical A pantropical ("all tropics") distribution is one which covers tropical regions of both the Eastern and Western hemispheres. Examples of species include caecilians, modern sirenians and the plant genera ''Acacia'' and ''Bacopa''. ''Neotropical'' ...

marine distribution.

Description

''Diodon eydouxii'' can be distinguished from many related species by its coloration. While its underside is silver to white in color, its back and sides are typically noticeably blue, with numerous small dark spots. The species is smaller than many of its congeners, reaching around in

total length Fish measurement is the measuring of individual fish and various parts of their anatomies, for data used in many areas of ichthyology, including taxonomy and fishery biology. Overall length Standard length (SL) is the length of a fish measured f ...

. It is believed that the blue coloration, comparatively

fusiform Fusiform (from Latin ''fusus'' ‘spindle’) means having a spindle (textiles), spindle-like shape that is wide in the middle and tapers at both ends. It is similar to the lemon (geometry), lemon-shape, but often implies a focal broadening of a ...

body, smaller size, and falcate fins of ''D. eydouxii'' are adaptations to its open-water environment, distinguishing it from non-pelagic (except as juveniles) species such as ''

Diodon hystrix Porcupinefishes or balloonfishes, are any of the various species of the genus ''Diodon'', the type genus of Diodontidae. Distinguishing features Fish of the genus ''Diodon'' have: * two-rooted, movable spines (which are derived from modified s ...

''.

Distribution and habitat

''Diodon eydouxii'' is known from the

Atlantic The Atlantic Ocean is the second largest of the world's five oceanic divisions, with an area of about . It covers approximately 17% of Earth's surface and about 24% of its water surface area. During the Age of Discovery, it was known for se ...

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is bounded by the cont ...

, and

Indian Indian or Indians may refer to: Associated with India * of or related to India ** Indian people ** Indian diaspora ** Languages of India ** Indian English, a dialect of the English language ** Indian cuisine Associated with indigenous peoples o ...

oceans, where it typically occurs in warm,

tropical The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

areas with a water temperature between . Unusually among members of the family Diodontidae, and unusually among members of

Tetraodontiformes Tetraodontiformes (), also known as the Plectognathi, is an order of ray-finned fishes which includes the pufferfishes and related taxa. This order has been classified as a suborder of the order Perciformes, although recent studies have found ...

in general, it is a

pelagic The pelagic zone consists of the water column of the open ocean and can be further divided into regions by depth. The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or water column between the sur ...

fish in all stages of its life cycle. It is typically found at depths of .

Ecology

''Diodon eydouxii'' is known to be a

schooling A school is the educational institution (and, in the case of in-person learning, the building) designed to provide learning environments for the teaching of students, usually under the direction of teachers. Most countries have systems of fo ...

species, distinguishing it from many tetraodontiform fish which are often solitary. It reportedly feeds on

ichthyoplankton Ichthyoplankton (from Greek: ἰχθύς, , "fish"; and πλαγκτός, , "drifter") are the eggs and larvae of fish. They are mostly found in the sunlit zone of the water column, less than 200 metres deep, which is sometimes called the ep ...

and other larger

zooplankton Zooplankton are the heterotrophic component of the planktonic community (the " zoo-" prefix comes from ), having to consume other organisms to thrive. Plankton are aquatic organisms that are unable to swim effectively against currents. Consequent ...

Relationship with humans

''Diodon eydouxii'' is known to be of some importance to minor commercial fisheries. It occasionally appears in the aquarium trade.

References

pelagic porcupinefish Pantropical fish pelagic porcupinefish Taxa named by Charles N. F. Brisout {{Tetraodontiformes-stub