Scale deformity descriptions for 23 species of fish, from various geographical areas and habitats

A renewed interest in fish scale anomalies prompted the present study, wherein we document a wide range of scale morphological abnormalities, including deformities in shape and structure, of a large number of species. In the present study, 63 cases of deformities were reported from 23 fish species collected from five countries. The abnormalities observed arc discussed within the framework of contaminated aquatic environments, with a goal of recognising the cause of abnormality. Deformed scales exhibited different shapes, showing both slight (n = 52 cases) and severe (n = 9 cases) abnormalities. The scale deformations described in the present study should help direct future work on the relationships between environmental condition and fish health.