This study reflects the current state of the fish fauna from the lower basin of river Bârlad, within the research started in 2003 in the hydrographic basin of this river regarding the inventorying of the species of fish from these waters. The lower basin and particularly the main course of river Bârlad have been seriously affected by water pollution, which led even to the extinction of the fish communities across the entire main course of the river, downstream of the city of Bârlad. This paper highlights the extent to which these fish communities have recovered, the data obtained being compared to that from 2003 and from the literature in order to identify the changes suffered by the structure of the fish communities. To this effect, investigations have been conducted in terms of species composition, the structure of fish assemblages, as well as the index of biological integrity (IBI) which best reflects the present condition of the fish stocks in these ecosystems.