Dive Pacific 175 Dec2020 Jan 2021

SPECIESFOCUS
Clown toado
~Canthigaster callisterna
By Paul Caiger
The clown toado or sharp-nosed pufferfish is
a species of sub-tropical origin distributed
throughout eastern Australia and the southwest
Pacific up to New Caledonia.
In New Zealand, whilst abundant at the Kermadecs,
it is also found in the north, especially in places
where the tropical currents reach (that is, islands and
headlands). Recent evidence suggests the species is
becoming more common at these places, likely as a
result of the warming seas around New Zealand.
The clown toado is a member of a very diverse genus
of pufferfishes, being one of 36 Canthigaster species.
It’s brightly coloured, green above and white below,
with two dark parallel stripes running along the body
and covered in iridescent blue wavy lines and dots
throughout. In courting males, the dark stripes fade
completely and the blues and greens become more
vivid (as depicted in the photograph).
Males are territorial and likely to breed with
females exclusively within their territory,
defending their boundaries against other males.
Like other pufferfishes, the clown toado possesses
one of the most potent naturally occurring toxins.
This neurotoxin called tetradotoxin (named after
the pufferfish family) is present in the skin and
other tissues of the fish, thus making it unpalatable
to predators. Their ability to ‘puff’ or inflate
themselves with water, together with their
poisonous skin and tissues, explains why these
small, slow-moving, colourful fish are often found
out in the open sand and rubble environs and not
predated upon by large piscivorous predators such
as snapper.
~Canthigaster callisterna
1 Also known as a sharp-nosed pufferfish or 6
clown toby.
2 Found in northern New Zealand but also 7
Australia and the SW Pacific.
3 15-20 cm in length.
8
4 One of 36 species in the genus Canthigaster.
5 Males defend territories, primarily for breeding.
Males display extravagant colouration during
courting.
Containing the pufferfish-specific neurotoxin,
tetrodotoxin which is highly poisonous if ingested.
Like all pufferfishes, will inflate itself with water
to become 3-4 times its size when alarmed.
56 Dive New Zealand | Dive Pacific