Question

The body of Rohu fish is covered by
a. Cycloid scale but the tail is homocercal
b. Placoid scale but the tail is heterocercal
c. Cycloid scale but the tail is heterocercal
d. Placoid scale but the tail is homocercal

Answer 1

Hint: Rohu is a teleost fish and the body of Rohu fish is covered by cycloid scales. Outer margin of the scales have a smooth feature. Grooves appear in the tail and are called homocercal. Rohu (habeorohita), belongs to class osteichthyes (bony fishes). Dermal scales are present on the body of Rohu. Equal lobes are present on the tails of Rohu.

Complete answer:
Roho labeo has bilaterally symmetrical body, moderately elongate body, dorsal profile more arched, cycloid scales are present on the body, scales are not present on the head, a pair of small maxillary barbels concealed in lateral groove, pharyngeal teeth in three rows, dorsal fin is inserted midway between snout tip and base 12-16 lateral line distinct, complete and running along median line. Lateral transverse scale- rows six or six and half between lateral line and pelvic fin base.

A homocercal tail is a type of caudal fin composed of two lobes of equal proportion. Caudal fins come in many symmetrical shapes. Heterocercal tail is also found in many animals which have unequal lobes.

Placoid scales are present on the body of sharks and rays and do not increase in size as fish grows. These are also known as denticles.

From the above information we know that the body of a Rohu fish is covered by cycloid scale but the tail is homocercal.
Hence, the correct answer is option (A).

Note: Rohu fish is also known as carpo fish. It is enriched with protein, omega 3, fatty acids and vitamin A, B and C that’s why it is commonly eaten by many people. Rohu should be eaten at least once a week for better nutrition. Fish cod liver oil is very useful for our body. It is very rich in vitamin A and reduces the risk of night-blindness. Rohu is mainly found in southern asia and is very important. It has a maximum length of 1m. Weeds and waste material are the main food source of the Rohu.