The fish which shows parental care is

Which of the following is a characteristic feature of $Osteichthyes$ (bony fishes)?

The air bladder in a fish helps in:

Bony plates and scutes are found in addition to scales in

Fishes having a swim bladder,which does not have direct communication with the exterior and where the resorbent and secretory parts are not sharply separated from one another,are called:

Air bladder occurs in