1. Their endoskeleton is made up of bones.
2. Body covered with cycloid, tinoid and ganoid scales. Some fish do not have scales. Such as- horn, Magur etc. Dr. Siddiq Publications
3. All body fins are bony and have dermal rays (lepidotrachea).
4. Their gills are covered with kanko.
5. Caudal fin homocircular type. That is, the tail fin is divided into two equal parts.
6. Their mouth is located at the tip.
7. Their brain consists of cerebellum, optic lobe and cerebrum.
8. There are 10 pairs of carotid nerves in the body.
9. The reproductive organs consist of four pairs of gills. On both sides of the head, there is a flower opening. Dr. Siddiq Publications
10. Air sacs are present in the body.
11. They breathe and float with the help of crackers.
12. Their heart is two-chambered and known as the venus heart.
13. They are unisexual animals. Excretion occurs. Direct and indirect effusion is observed.
[key words to remember features: endoskeleton, cycloid, tenoid, ganoid, cutaneous ray, conch, homocercal, pore, brain, carotid nerve, gill, air sac, heart]