Behavioral endpoints serve as valuable tools to
distinguish and evaluate effects of exposure to
environmental stressors, and fish behavioral al-
terations can provide important indices for eco-
system assessment (Kane et al., 2005). Through-
out the study period fish exhibited low behavioral
stress responses when exposed to sub-lethal con-
centration of salinity (12ppt). Impatience or agi-
tated activeness or erratic movements were ob-
served when exposed to lethal concentrations
(14ppt and 16ppt). From the beginning up to 3
hours of the lethal salinity exposure fish showed
frequent movement from surface to bottom, ag-
gression and sometime showed jumping activity.
In addition, fish expressed highly increased oper-
cular movements accompanied by excessive se-
cretion of mucus which indicating respiratory
distress of fish. Lawson and Anetekhai (2011)
and Aysel and Ayhan (2010) also noted similar
behavioral stress responses after exposing fish in
higher salinities.