Nowadays, it is important to consider environmental issues, as ecological problems and their severe effects are intensifying in Iran, particularly in Khuzestan province. The environmental effects of hydroelectric plants are highly regarded due to their significant impact on an extensive area. Lack of safe path for fish passing through the turbines is one of these damages. In order to deal with these challenges, researchers are trying to optimize hydro power turbines. In this optimization, old runners were replaced. Meanwhile, conditions of fish passing through the turbines and fish survival have been improved. Considering the existence of six hydroelectric power plants in Khuzestan province, it would be possible to conduct optimization or constructing studies with a fish-friendly approach for the safe passage of fishes to slightly reduce the extent of environmental damages.