Top of the Food Chain
Porcupine Puffers of the Genus Diodon
inhabiting floating debris and sargassum
in the open oceans. In some species, the
juveniles will be found in estuaries or
lagoons. Occasionally juveniles will form
small groups, but we tend to not call these
schools, as there is little organization to
them and they are more just gatherings, and
the members of such groups tend to simply
find common comfort amongst either
each other or in the provided shelter. One
species, D. eydouxii (pelagic porcupinefish)
is pelagic throughout all lifestages.
Their bodies are robust and their teeth
are united in each jaw, but they lack
a central division. The body is covered
with long, sharp spines, which are folded
backward when the fish is not inflated.
The dorsal region of the caudal peduncle is
spiny, as is the belly.
Brian M. Scott graduated
from The Richard Stockton
College of New Jersey with a
Bachelor of Science Degree in
biology and a minor in marine
biology. Brian has authored
or co-authored five books
on aquarium fishes and has
published more than 75 articles
dealing with all aspects of the
aquarium hobby in various
popular magazines. Today,
Brian is a wildlife biologist
for a private environmental
consulting firm in his home
state of New Jersey, where he
is involved in a radio-telemetry
study with the northern pine
snake in the NJ Pine Barrens.
i s Diodon ge nus T he circumtropical in distribution. Two species, D. hystrix and D. holocanthus, are the most popular
of the group and most often found for sale
in the aquarium trade. Many specimens
are imported from the Caribbean and the
Pacific, but both species have far larger
distributions and may be imported from
other regions as well. These are large fish
that get between 2 and 3 feet in length, so
they require extremely large tanks.
Diodon are generally nocturnal predators.
They are typically found in and among reefs,
rock piles, and other submerged structures.
In aquaria they quickly learn to switch
their activity to times when the tank is
illuminated; however, they will still remain
quite active after the lights are turned off.
Sometimes such nocturnal activity disrupts
tankmates, so it is important to have many
rocks and other decorations to where the
other fish can safely retreat.
Porcupine puffers are usually not
aggressive in the sense that they will
harass other species on a regular basis.
Be forewarned, though, that just as with
all species of fishes there are exceptions,
and highly aggressive specimens may
be encountered. Additionally, the larger
the puffer is when collected for the
aquarium trade, the more likely it is to
be intolerant of other fishes when housed
in an aquarium. For this reason, it’s
almost always best to introduce smaller
specimens to your aquarium.
Diodon are large-growing omnivorous
fishes of the family Diodontidae (puffers
and burrfishes). Adults and sub-adults
are benthic, while juveniles are pelagic—
Puffers are Not Toys!
Like all puffers, the porcupines have the
ability to inflate their bodies with water,
or air. In most cases, puffers will do this
if they feel threatened—specifically if they
feel as if they may get swallowed. Porcupine
puffers are somewhat unique in the sense
that when they inflate their bodies, the
quills that are usually laid flat against the
body protrude to form a formidable barrier
of intensely sharp spines between the skin
of the puffer and the potential predator’s
While it may be fun to watch a puffer
inflate, deflate, and then re-inflate its body—
which is most easily done by removing it
from the water then placing it back in, and
removing it again—such behavior causes
severe distress to the puffer and can be
fatal. When a puffer inflates naturally, it
normally fills itself with water, not air.