| Phylum Chordata
> Subphylum Vertebrate > fishes |
Frogfishes
Family Antennariidae
updated
Oct 08
if you
learn only 3 things about them ...
They are fishes that go fishing! They use lures to attract
prey.
They are awkward swimmers, but they have the fastest mouth!
Hard
to spot: they resemble sponges, rocks. So watch your step! |
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Where
seen?
These rotund fishes are sometimes seen on some of our shores. They
are probably quite common and often simply overlooked as they are
extremely well camouflaged.
What are frogfishes? Frogfishes
belong to the Family Antennariidae. According to FishBase,
the family has 12 genera and 41 species.
Why the name frogfish? These fishes were previously
called anglerfishes, a much more appropriate name for these ambush
predators. But anglerfish is now a common name reserved for deep sea
fishes that also use a lure to attract prey within their reach.
Features: To about 18cm, but those encountered about 6-10cm
long. The frogfish has a rounded body that can expand greatly. A handy
feature that allows the fish to swallow prey as large as itself. Not
a fast swimmer, the frogfish usually lies motionless near coral rubble,
blending perfectly with its surroundings. Here it waits to ambush
passing prey. It doesn't have scales and instead, has a loose prickly
skin. Covered with filaments and fleshy bits, it looks just like an
algae-covered rock.
Frogfishes come in a wide variety of colours and patterns. Some species
are brightly coloured to mimic sponges or other colourful reef creatures.
According to Kuiter, the young of some species of frogfishes sometimes
look like poisonous nudibranchs.
Sometimes mistaken for stonefish
and scorpionfish. Here's more on how
to tell apart fishes that look like stones.
Fishing
with a lure: The
frogfish literally lures prey to come closer. The lure is at the top
of its head, just above its very large, upward facing mouth.The lure
is made up of the first spine of the dorsal fin. The spine is modified
into a rod or stalk (called the illicium) tipped with a fleshy, fluffy
or otherwise attractive bit (called the esca). This bit is wriggled,
jerked and waved about so it appears to be a helpless and tasty little
morsel. While the fish itself remains motionless, looking like just
another lump of rock or other harmless thing. Unsuspecting creatures
that attempt to eat the lure are instead eaten by the frogfish!
The victim is usually swallowed whole in one gulp of the frogfish's
huge mouth. The frogfish can hugely expand its mouth in less than
a second, making it among the fastest capture in the animal kingdom.
Each frogfish species usually targets a specific prey and each species
has a lure that resembles something the targeted prey would find tasty.
When not in use, the lure is safely flattened against the head.
What do they eat: Frogfishes generally
eat other fishes although some temperate species eat crustaceans.
They may even eat other frogfishes, including their potential mates!
Fish with arms?! The frogfish
has another unusual feature: limb-like pectoral fins with an elbow-like
joint. These look almost like 'paws'. It uses these fins almost like
arms and hands, to grip the surface and 'walk' slowly about (more
of a waddle actually). It also has clasping pectoral fins under its
body.
The frogfish has tube-like gill openings under the base of its pectoral
fins. This prevents exhalations from betraying its presence. It is
said that the openings can also be used for jet-propelling. Its eyes
are at the top of its head. Gill openings are reduced to small round
holes.
Frogfish babies: A frogfish mother
lays thousands of eggs embedded in a large floating gelatinous mass
called an 'egg raft' or 'veil'. Several species carry their eggs attached
to their bodies.
Unusual frogfishes: While most
frogfishes are bottom-dwelling, one species (Histrio sp.) floats
among sargassum seaweed. Another species, the Brackishwater frogfish
(Antennarius biocellatus) inhabits brackish and even totally
freshwater habitats.
Status and threats: Our frogfishes
are not listed among the threatened animals of Singapore. However,
like other creatures of the intertidal zone, they are affected by
human activities such as reclamation and pollution. Over-collection
by hobbyists can also have an impact on local populations.
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Family
Antennariidae recorded for Singapore
from
Wee Y.C. and Peter K. L. Ng. 1994. A First Look at Biodiversity
in Singapore.
*Lim, Kelvin K. P. & Jeffrey K. Y. Low, 1998. A Guide to the Common
Marine Fishes of Singapore.
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Frogfishes
seen awaiting identification |
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Antennarius
caudimaculatus
Antennarius chironectes
Antennarius hispidus (Shaggy frogfish)
*Lophiocharon trisignatus (Spotted-tail
frogfish) |
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