Question

characteristics of Bony fish​

Answer 1

Answer:

Following are the characteristics of bony fish:

1. They have swim bladders to control their buoyancy.

2.Bony fish breathe by moving water across their gills

3. Most bony fish have three pairs of gill arches.

4.The bodies of bony fish are covered with smooth scales.

Answer 2

Answer:

13 Characteristics of bony fishes or class Osteichthyes are as follows-

Explanation:

1. They are found in different water types such as fresh, brackish, or salt; warm or cold
2. Body of bony fishes is spindle-shaped and streamlined.
3. Fins are both median and paired and are supported by fin rays made up of cartilage or bone. The tail is usually homocercal,
4. Skin consists of many mucous glands, usually implanted with dermal scales of 3 kinds- cycloid, ctenoid & ganoid. Some bony fishes are without scales. Placoid scales are absent in them.
5. Endoskeleton is mainly made up of bone (osteon means bones and ichthyes means fish).
6. The notochord is replaced by distinct vertebrae. The pelvic girdle is usually small and simple or absent. Claspers are also absent.
7. Mouth is terminal or subterminal. Teeth are present in the jaws. Cloaca is absent but the anus is present.
8. Respiration occurs by 4 pairs of gills present on bony gill arches, covered by a common operculum on either side.
9. An air (swim) bladder is often present with or without a duct connected to the pharynx.
10. Ventral heart is 2-chambered means 1 auricle and 1 ventricle. Sinus venosus and conus arteriosus are present. Aortic arches are of 4 pairs. Erythrocytes are oval and nucleated. (poikilothermous). A ureotelic form of excretion is present.
11. Small olfactory lobes & cerebrum along with well-developed optic lobes, and cerebellum are present in the brain. Cranial nerves are of 10 pairs.
12. Well-developed lateral line system is there. The internal ear is present with 3 semicircular canals. Kidneys are mesonephric. with variable Excretion Temperature.
13. Sexes are separate with the presence of paired Gonads. Fertilization is usually external. Most bony fishes are oviparous, rarely ovoviviparous or viviparous. The size of eggs is minute to 12 mm. The cleavage is meroblastic. Development is direct and rarely with the occurrence of metamorphosis.