Definitions

toadfish

toadfish

[tohd-fish]
toadfish, common name for the sluggish, bottom-feeding fishes of the genus Opsanus, found in the shallow waters from New Jersey to the Caribbean. Toadfishes feed almost entirely on crustaceans and small fishes. The head of a toadfish is broad and flat, with barbels and fleshy fringes, sharp gill covers, and spiny protrusions on the cheeks; the mouth is enormous and has many sharp teeth. The scaleless, slimy body tapers to a slender tail. Toadfishes grow to 1 ft (30 cm) in length. The eggs, sometimes laid in empty shells or tin cans, are guarded viciously by the male. The midshipmen (Porichthys species) of the same family are deepwater fishes of the Atlantic and Pacific oceans, with many small luminescent organs on the underside of the body. Other members of the family are found in tropical waters and have venomous spines. Toadfishes and their relatives are classified in the phylum Chordata, subphylum Vertebrata, class Osteichthyes, order Batrachoidiformes, family Batrachoididae.

Oyster toadfish (Opsanus tau).

Any of about 45 species (family Batrachoididae) of heavy-bodied, carnivorous, bottom-living fishes, found chiefly in the New World and mostly in warm seas. Toadfishes, up to 16 in. (40 cm) long, have a broad, flattened head, a large mouth, strong teeth, and small scales (if any). Most produce grunting or croaking sounds. The oyster toadfish (Opsanus tau) is common in shallow eastern North American coastal waters. Venomous toadfishes (genera Thalassophryne and Daector), of Central and South America, have venom-injecting spines on their dorsal fins and gill covers. Midshipmen (genus Porichthys), shallow-water American fishes, have rows of 600–840 buttonlike light organs along the body.

Learn more about toadfish with a free trial on Britannica.com.

This article is about the fish; for the fictional television character, see Toadfish Rebecchi.
The toadfish comprise the family Batrachoididae, the only family in the ray-finned fish order Batrachoidiformes. Both the English common name and scientific name refer to their toad-like appearance (batrakhos is Greek for frog). There are 69 species in 19 genera, most of which are marine in distribution though some are found in brackish water and one subfamily, the Thalassophryninae, is found exclusively in freshwater habitats in South America. Toadfish are benthic ambush predators that favor sandy or muddy substrates where their cryptic coloration helps them avoid detection by their prey. The dorsal fin and gill cover spines on the toadfishes of the subfamily Thalassophryninae are hollow and will inject venom into any predator attempting to eat the fish. Its dorsal fins and opercular spines are so poisonous, that eating them may result in serious illness or death.

Toadfish are well known for their ability to "sing", males in particular using the swim bladder as a sound-production device used to attract mates. The Western Atlantic species Opsanus tau known as the oyster toadfish is quite widely used as a research animal, while a few species, most notably Thalassophryne amazonica, are occasionally kept as aquarium fish.

Morphology

Toadfishes are usually scaleless, with eyes set high on large heads. Their mouths are also large, with both maxilla and premaxilla. The gills are small and occur only on the sides of the fish. The pelvic fins are forward of the pectoral fins, usually under the gills, and have one spine with several soft rays. There are two separate dorsal fins, the first smaller dorsal fin with spines; and the second larger and longer dorsal, with from 15 to 25 soft rays. The number of vertebra range from 25 to 47.

Toadfishes of the genus Porichthys, the midshipman fishes, have photophores and four lateral lines, while the Thalassophryninae are venomous, with a total of four hollow spines (two dorsal and one on each gill-flap (opercle)) connecting to venom glands and capable of delivering a painful wound.

Distribution

Toadfish are found worldwide. Almost all are marine, but Daector quadrizonatus and Thalassophryne amazonica are known from Colombia (Atrato River) and the Amazon River, respectively.

Habits

Toadfishes are bottom-dwellers, ranging from near shore areas to deep waters. They tend to be omnivorous, eating sea worms, crustaceans, mollusks and other fish. They often hide in rock crevices, among the bottom vegetation, or even dig dens in the bottom sediments, from which they ambush their prey.

Males make the nests and guard them after the female lays the eggs. The male attracts the female by "singing", that is by releasing air by contracting muscles on their swim bladder. The sound has been called a 'hum' or 'whistle'.

Economics

Toadfish are not normally commercially exploited, however, they are taken by local fishermen as a food fish, and by trawlers where they usually end up as a source of fishmeal and oil. Some smaller toadfish from brackish-water habitats have been exported as fresh-water aquarium fishes.

References

  • Nelson, Joseph S. (2006) "Order Batrachoidiformes" Fishes of the World (4th ed.) John Wiley & Sons, Hoboken, NJ, ISBN 978-0-471-25031-9 pp. 248-249;
  • Collette, B. B. "Order Batrachoidiformes, Batrachoididae, Toadfishes." In Carpenter, Kent E. (ed.) (2002) The living marine resources of the Western Central Atlantic Vol. 2, Bony fishes. Pt. 1 Acipenseridae to Grammatidae Food and Agriculture Organization of the United Nations, Rome (Special publication of the American Society of Ichthyologists and Herpetologists no. 5) ISBN 9251048266 ;
  • Collette, B.B. and J. L. Russo (1981) "A Revision of the Scaly Toadfishes, Genus Batrachoides, with Descriptions of Two New Species from the Eastern Pacific" Bulletin of Marine Science 31(2): pp. 197–233;
  • Hutchins, J.B. (1976) "A revision of the Australian frogfishes (Batrachoididae)" Records of the Western Australian Museum 4(1): pp. 3-43;
  • CBC Radio Quirks and Quarks show podcast segment on unique toad fish habits with links to primary sources.

See also

External links

Search another word or see toadfishon Dictionary | Thesaurus |Spanish
Copyright © 2014 Dictionary.com, LLC. All rights reserved.
  • Please Login or Sign Up to use the Recent Searches feature