Scales are calcium carbonate and collagen-contained structures embedded within the fish epidermis and useful for
species identification. This study aimed to describe morphological characteristics of scales and use the differences to
prepare keys to species. Fishes were sampled from selected rivers of Tembat Forest Reserve, Hulu Terengganu. Specimens
caught were from 3 families (Cyprinidae, Channidae, Nandidae) and 17 species. Each species was represented by ten
individuals (size ranges 2.5 - 50 cm TL). The scales were removed, soaked in H2
O2
(0.5%), NH3 (0.3%), DH2
O and
mounted between a pair of glass slides for digital photographing. The morphological descriptions were based on types
of scales, distinctiveness of radii arrangement at the anterior field, radii cover, radii distribution, overall shape, focus
position and focus pattern. Keys to species were constructed based on these scale morphological characters described.
Measurements of scale total length (L), total width (W), rostral field length (L1) and caudal field length (L2) of the scales
were taken using Image J software. The inter-specific variation among scales was indicated by L1/L, L2/L, L1/L2 and
W/L indices through multiple comparison tests (ANOVA). It was found that all 17 species showed significant differences
with at least one other species in all four indices. Pristolepis grootii (Bleeker 1852) was the only one that significantly
different (p<0.05) from other 16 species in the first three indices. Species that showed the least significant differences
among species was Probarbus jullieni (Sauvage 1880). The differences among the scales were primarily due to the
different types of scale that was either ctenoid or cycloid.