By Dr J Floor Anthoni (2007)
Rock pool fishes are best identified from
pictures. This page covers the most commonly encountered intertidal fishes
in New Zealand, ranging from visitors to permanent inhabitants of the intertidal
rocky shore. New Zealand has many species of triplefin, and these often
look very similar.
Fish Fishes have internal skeletons and all those
found on the rocky shore have bony skeletons, unlike the cartilageous bones
of sharks and rays. Living in a wave-washed environment is taxing unless
one is small and one can hold oneself firmly in place. Triplefins do this
by means of extended breast fins (pectorals), the rockfish by its
rubbery back fin (dorsal) and clingfish by their modified hip fins
Fishes are easy to identify once they show themselves,
one would think. But many species have a range of costumes (variable colour
patterns), which makes them very difficult to tell apart.
f039805: in order to be able to live on the rocky shore,
fish need to be really small. So only the young of common fishes can be
found here, such as young spotties (Crenilabrus celidotus). Spotties
are born female, so it highly unlikely to find male spotties in a rock
pool. In the background a variable triplefin.
f036907: a very young sweep (Scorpis lineolatus) is
silver coloured with red specks on its side and a green back as it settles
out from its planktonic babyhood. It is commonly found underneath overhangs
in rock pools, in spring/summer.
0609149: the olive rockfish (Acanthoclinus fuscus)
is easily identified from its eel-like shape and long back fin with bent-back,
rubbery, finrays. It also often has a white stripe over its snout, but
can also discolour itself to jet black. The rockfish can live for hours
out of the water, which helps it to guard its nest of pink eggs under a
stone, high up the intertidal. The rockfish can grow to 30cm in length.
Several species are known in NZ, but only this one is common on the rocky
shore. It is a predator, feeding on small crabs, shrimps, sea lice and
f050430: a 30mm young lumpfish (Trachelochismus pinnulatus)
is because of its neck patch, difficult to see, even though they may be
quite common. Taking this photo took much patience.
f050604: A mature lumpfish (Trachelochismus pinnulatus)
has a blunt snout, coloured body (yellow, green, brown, reddish) with longitudinal
stripes and spots on its head. It can grow to 100mm length.
f050622: the lumpfish lays its eggs upside down under a stable
rock. First these look red (on left), but soon turn transparent with two
blue eyes peeping through (on right). The eggs are laid neatly and equally
05062206: closeup of clingfish suction disc of a lumpfish
stuck to an aquarium window shows the large breastfin (pectoral) and modified
f040429: the urchin clingfish (Dellichthys morelandi),
as its name suggests, is often found underneath sea urchins where also
bugs of all kind shelter. With its slender form and pointed snout, the
urchin clingfish manages to snatch these bugs from inbetween a forest of
spines and suckerfeet.
the orange clingfish (Diplocrepis puniceus) is kite-shaped
and very cute. It is no longer common.
f051707: the crested blenny (Parablennius laticlavius)
is club-shaped with a large blunt head and slender body with a black stripe.
It has only one long backfin. These 'slimefish' do not have scales and
can live to a ripe old age. They are also rather swift and smart,
and are therefore difficult to catch or to photograph.
f032803: the crested blenny (Parablennius laticlavius)
is a shy little fish, easily recognised by its thin black stripes and a
crest over each eye. The crested blenny seeks out a snug fitting hole in
which it can withdraw itself entirely. From this position it can maintain
a cleaning station visited by fish who want their nits (sea lice) picked
f050618: the common or pebble triplefin (Fosterygion lapillum)
begins its life in this striped costume, looking a bit like a crested blenny
with its two black stripes. The fish shown here is only 25mm long, and
is easily overlooked in rock pools, and when it moves, it is so fast that
it is often not noticed. (L: lapillum= pebble)
f034129: common triplefin (Fosterygion lapillum)
or cobble triplefin in a light costume.
f049623: the common triplefin can also colour its back fin
red, and its entire body between white to yellowish to olive to black.
f033705: when spawning, the common triplefin becomes entirely
black with a bright white margin on its anal fin.
f032212: the variable triplefin (Fosterygion varium)
has many costumes but never a black line. Its snout is often red. It has
a relatively large mouth.
f034125: the variable triplefin in one of its light suits.
It can also look like the common tyriplefin in any of its dark suits, but
it is almost twice as large.
f033737: the speckled triplefin (Grahamina capito)
has many speckles over its entire body which is usually evenly coloured.
It also often has a red backfin.
f050615: speckled triplefin in a light suit. Speckled triplefins
are much less common than variable triplefins.
f033700: the spectacled triplefin (Ruanoho whero)
is easy to recognise from its dark eyes joined by a dark band, as if it
were wearing 'shades'. But it too has many costumes. This is a shy fish,
usually living underneath safe rocks.
f033707: in its spawning costume, the spectacled triplefin
loses its spectacles.
f034609: the mottled twister (Bellapiscis lesleyae)
or rockpool triplefin is a small fish with mottled olive-green colour,
blunt snout, thick lips and large breast fins. It is named after its zig-zag
side band. It does not seem to assume various costumes.
f034521: the cryptic triplefin (Cryptichthys jojettae)
lives in the most turbulent of waters, often resting on the sheltered sides
of rocks. As its name suggests, it is hard to see. It too has various costumes.
f035602: the robust triplefin (Fosterygion robustum)
is easily confused with the common triplefin, but it lacks the horizontal
stripe and is black-speckled all over. It is more common around the South