A record of anopthalmia in Mystus tengara (Hamilton, 1822) from Assam

Abstract

An abnormal case of anopthalmia in a striped catfish Mystus tengara (66.8 mm in standard length) from Assam is reported in this communication. Thirty eight morphological characters of the abnormal specimen were also studied and compared with normal specimens to observe variation in the morpho-meristic traits, if any. In the abnormal specimen, the proportionate height of the dorsal fin (31.1 mm) and nasal barbel length (75.9 mm) was found to be higher compared to that of the normal specimens (21.6 -26.5 mm and 47.9 -72.5 mm, respectively). While the body depth of anus was higher in case of normal specimens (19.1 -29.2 mm) compared to abnormal specimen (14.5 mm). However, no marked variation was observed in meristic characters. This anomaly does not seem to have affected morphological aspects. Factors like weed infestation, pesticide and herbicide application adversely affecting the habitat is believed to be the cause of such deformity. The abnormality does not seem to have affected the overall growth of the fish.