Taxonomy of Finfish

2.1.6.4 Scales

Scales are thin bony plates covering the whole ofpart of the body of the fish. They can be microscopic as in the cobitids, small as in Chela, large as in Labeo and big as in Mahseers. Their edges may be spinous (ctenoid Fig. 32 A, B Butis butis, Ophiocara species of Eleotridae), or looth (cycloid Fig. 32 C, D). Most fishes have the latter variety. The numbers Vary according to the size; it may even exceed 100 (Securicula), limited to 87 or even less than 20 Puntius titeya). Most are deciduous in that they fall off easily. In some fishes the scales are in the form of bony plates (Puffer fishes).

 

The variations in the different body parts of the fish have been outlined mainly to indicate that these are very helpful and often used in separating taxa.

 

 Fig 32 Added

Abdomen

The Abdomen of a fish is mostly rounded except in flat fishes, hill stream fishes and deep sea fishes where they are flat. In most Cyprinids the abdomen may be keeled with no barbels (Fig. 33 A) or rounded with barbels (Fig. 33 B).

In CIupeids the ventral profile may be with serrations (Fig. 33 C). ,In the Sisorid fish Glyptothorax an adhesive apparatus is developed (Fig. 33 D) in which the paired fins, pectoral and pelvics, may be plaited (Fig. 33E).

Fig 33 Added