Natural history

Bony fishes occur from polar seas to equator, from surface to depths in waters more than 12,000 feet deep. They live variously in open water, sandy, rocky or muddy bottoms, in crannies of reefs, in saline bays, estuaries, fresh alkaline rivers, lakes and cave water, and hot and cold springs. Most fishes migrate from salt water to fresh-water (anadromous) and fresh-water to salt water (catadromous) for spawning. They are important human protein food. The class Osteichthyes comprises of bony fishes, which are famous for their bony skeleton, scales, plates, air bladder and advanced brains. Various fishes are found in different types of water such as fresh-water, brackish water, salt water, warm water and cold water

• Skeleton chiefly of bone (Cartilage in sturgeon)
• Skin with many mucous glands with embedded bony dermal scales (Cycloid, ctenoid or ganoid).

Sub-class A. Actinopterygii

• Ray-finned fishes. Paired fins thin, broad, without fleshy basal lobes and supported by dermal fin rays.
• Nostril not connected to mouth cavity except in stargazer.

Superorder I. Chondrostei

• Primitive ray-finned fish or cartilaginous ganoids.
• Tail fin heterocercal.

Order 1. Polypteriformes

1. 1. Body slender. Scales thick ganoid and rhombus.
   2. 8 or more dorsal fins, each preceded by a spine. Caudal fin arrow shaped.
      Example :- Polypterus

Order 2. Acipenseriformes

1. 1. Snout long or paddle shaped.
   2. 8 rows of bony ganoid scutes or body naked with few vestigeal scales.
      Example :- Acipenser, Polyodon.

Superorder II. Holostei

• Intermediate forms between Chondrostean and teleost fishes.
• Scales ganoid. Ray finned fishes.

Order 1. Amiiformes

1. 1. Snout normal. Dorsal fin long. Tail fin short.
   2. Scales thin, Overlapping and cycloid.
      Example :- Amia (bow fin).

Order 2. Lepidostiformes

1. 1. Snout and body elongated.
   2. Scales rhomboidal, ganoid, in oblique rows.
      Example :- Lepidosteus.

Superorder III. Teleostei

• Light skeleton. Density of bones reduced. Ganoid scales reduced or absent.
• Swim bladder hydrostatic.
• Modem ray-finned fishes

Order 1. Clupeiformes

1. 1. Silvery compressed marine fishes. Scales cycloid.
   2. Air bladder connects to pharynx. Tail fin homocercal. Pelvic fin abdominal.
      Example :- Clupea, Salmo, Tarpon, Sardinops and Esox.

Order 2. Ostariophysi or Cypriniformes

1. 1. Air bladder communicates to pharynx.
   2. Weberian ossicles between air bladder and internal ear.
      Example :- Characius, Electric eels, Suckers, Minnows, Catfishes, Lobeo, Mystus, Notopterus, Electrophorus, Cyprinus, Barbus, Arius,
      Clarius, Wallago, Catla, Heteropneustes

Order 3. Ophiocephaliformes

1. 1.  Head depressed with plate like scales.
   2.  Air bladder long without duct
   3. Accessory respiratory organs present.
      Example :- Ophiocephalus (Channa)

Order 4. Anquilliformes

1. 1. Eels. Body long and slender.
   2. Dorsal, caudal and anal fins continuous. Pelvic fins absent.
      Example :- Anguilla, Muraena and Amphipnous.

Order 5. Beloniformes or Synentognathi

1. 1. Pectoral fins large and high on body.
   2. Scales cycloid.
      Example :- Flying fishes. Exocoetus, Belone, Cypselurus, Scomberesox

Order 6. Syngnathiformes or Solenichthyes

1. 1. Snout tubular with suctorial mouth. Swim bladder closed.
   2. Bony rings or protective scales over body.
      Example :- Hippocampus, Hemirhamphus, Xenantodon, Syngnathus, Fistularia.

Order 7. Perciformes or Percomorphi

1. 1. Trout perches. Dorsal and anal fins preceded by 1 or 4 spines. Pectoral fin well up on sides.
   2. Weberian apparatus absent. Air bladder without duct.
      Example :- Anabas (Climbing perch), Perea, Lates, Huga, Lepomis, Scomber.

Order 8. Pleuronectiformes

1. 1. Asymmetrical head with both eyes on one side.
   2. Body strongly compressed. Dorsal and anal fins fringing the body.
      Example :- Pleuronectes, Hippoglossus, Achirus, Synaptura, Solea.

Order 9. Tetradontiformes (= Plectognathi)

1. 1. Body shape variable. Some globose.
   2. Strong jaws with sharp teeth. Scales generally spiny.
      Example :- Ostracion, Diodon, Tetradon, Molamola, Fieraster.

Order 10. Echeiniformes

1. 1. Dorsal fm modified into flat, oval, adhesive disc on upper surface of head.
   2. Scales cycloid. Air bladder absent.
      Example :- Echeneis or Remora

Order 11. Lophiiformes

1. 1. Dorsal fin like flexible spines.
   2. First dorsal spine located on head with tip modified into lure. Mouth wide.
      Example :- Lophius, Antennarius