Summary The feeding ecology of Mystus tengara (Hamilton, 1822) was studied in the Tanore wetland of Rajshahi, northwestern Bangladesh from January 2011 to December 2011. In fish purchased from the local market, a total of 14 713 food items were identified in the stomach contents of 3191 M. tengara specimens, an omnivorous catfish with a diversified feeding strategy including cladocerans, copepods, rotifers, gastropods, green algae, diatoms, insects, ‘small fish remains, fish fry and eggs’ and ‘other’ food items. Insects were the most dominant group of prey throughout the year. Seasonal changes in diet composition were due to the availability of prey items and fish size. Ontogenetic changes were noted between the juveniles and adults. The gut contents of M. tengara showed that the food items were from different layers of the water bodies.

The present study was the detailed investigation to identify maturity of female Mystus tengara in the Ganges River of Rajshahi (24°22´N; 88°35´ E), northwestern Bangladesh. Specimens (n = 921) were collected monthly from January to December 2015, using cast nets (mesh size = 17 mm) for adults and purse-seine and trap nets (mesh size = 4 mm) for juveniles. Histological analyses of 171 females were performed in which oocyte development was divided into five stages, with the oocyte size range from 33 to 1609 µm in diameter. The ovarian cycle of Mystus tengara was divided into three periods: a long period of early oogenesis (emerging from December but expands to April as the initiation time of early oogenesis for all the oocytes were not similar), a short period of vitellogenesis (February to April) and a spawning period from M ay through July with peak activity in June. Both gonadosomatic (I G ) (up to 16.2%) and hepatosomatic indices (I H ) (up to 3.7%) can be used together to predict the spawning period where the females were observed to spawn in June and July. Total lengths at minimal observed maturity/50% maturity (L T50 )/95% maturity (L T95 ) values were 7.9/8.9/11.1 cm for females. Mystus tengara is likely an asynchronous multiple spawner with indeterminate fecundity .