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Phylum Chordata > Subphylum Vertebrate > fishes
Frogfishes
Family Antennariidae
updated Oct 2016
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!

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. 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! 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.

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.

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.

Changi, Jun 08


Lure on the head


Limb-like pectoral fins


A large mouth!
Pulau Hantu, Jan 06



Very well camouflaged!
Tuas, Aug 04

Frogfishes on Singapore shores

 

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.
**from WORMS

  Frogfishes seen awaiting identification
  Black frogfish

  Family Antennariidae
  Antennarius caudimaculatus=**Antennarius commerson (Commerson's frogfish)
Antennarius chironectes=**Antennarius pictus (Painted frogfish)
Antennarius hispidus
(Shaggy frogfish)
*Lophiocharon trisignatus
(Spotted-tail frogfish)

Links
References
  • Tan Heok Hui. 29 August 2014. Egg brooding behaviour of the spot-tail frogfish, Lophiocharon trisignatus. Singapore Biodiversity Records 2014; 237-238.
  • Wee Y.C. and Peter K. L. Ng. 1994. A First Look at Biodiversity in Singapore. National Council on the Environment. 163pp.
  • Allen, Gerry, 2000. Marine Fishes of South-East Asia: A Field Guide for Anglers and Divers. Periplus Editions. 292 pp.
  • Kuiter, Rudie H. 2002. Guide to Sea Fishes of Australia: A Comprehensive Reference for Divers & Fishermen New Holland Publishers. 434pp.
  • Lieske, Ewald and Robert Myers. 2001. Coral Reef Fishes of the World Periplus Editions. 400pp.
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