Characteristics

- Many have a swim bladder air sac for buoyancy
- Marine and freshwater
- Range in size from 1cm to more than 6m long
- The skeleton of bony fishes is reinforced by a hard matrix of calcium phosphate
- Skin is covered with flattened bony scales
- Glands in the skin of the fish secrete a mucus that gives the animal it characteristic sliminess
- Inhabit almost every body of water. They are found in tropical, temperate, and polar seas. Bony fishes exist in fresh water, seawater, and brackish environments.
- Most have a fusiform (rounded and tapering at both ends) body shape. This
- Body shape reduces drag and requires a minimum amount of energy to swim.
- Have an inner ear for equilibrium, detecting acceleration, and hearing
- Bony fish have taste buds inside their mouths
- The slowest swimming bony fish is the eel, the fastest, the sailfish Istiophorus platypterus, has been clocked at 100km/h.

Reproduction

- Most species have external fertilization and lay large numbers of eggs
- Become sexually mature at various ages
- Most fishes do not care for the young

Respiration

- Respiration mainly through gills
- Water enters the gill chamber through the mouth
- Blood in the gill filaments absorb oxygen form the water
- Water exits through gill opening located under the operculum
- Some species can absorb oxygen through the skin

- Bony fishes have a heart with two chambers: the atrium and the ventricle. The venous side of the heart is preceded by an enlarged chamber called the sinus venosus. The arterial side of the heart is followed by a thickened muscular cavity called the bulbus arteriosus
- Oxygenated blood flows from the gill filaments to the organs of the head and body. A complex system of arteries, veins, and capillaries circulates blood through the body.

Digestive system

- The esophagus in bony fishes is short and expandable so that large objects can be swallowed. The esophagus walls are layered with muscle
- Most species of bony fishes have a stomach. Usually the stomach is a bent muscular tube in a "U" or "V" shape. Gastric glands release substances that break down the food to prepare it for digestion
- The pancreas secretes enzymes into the intestine for digestion
- The intestine is where the majority of food absorption takes place. The length of the intestine in bony fishes varies greatly.
- Herbivorous bony fishes generally have long, coiled intestines, and carnivorous bony fishes have short intestines
- The digestive system terminates at the anus

Good Links
http://pc65.frontier.osrhe.edu/hs/science/bfish.htm
http://www.washington.edu/burkemuseum/bonyfish.html
http://www.flmnh.ufl.edu/fish/Education/Diagrams/FishBodyParts.html

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