Which of the following types of scales is the most common in teleosts?

Correct option is C

Correct Answer: (c) Cycloid
Explanation:
→ Cycloid scales are the most common type found in teleost (bony) fishes, especially soft-rayed fishes.
→ They are smooth-edged, thin, flexible, and allow easy body movement.
→ Composed of collagen and hydroxyapatite arranged in concentric rings.
Information Booster:
→ Growth rings (circuli) on cycloid scales help in age determination.
→ Common in carps, salmonids, and minnows.
→ Provide protection without restricting swimming agility.
Additional Information (Other Options):
(a) Cosmoid – found in fossil lungfishes.
(b) Ganoid – found in gars, sturgeons.
(d) Ctenoid – toothed scales typical of spiny-rayed fishes.