Chlorine elevated >0.5mg/L
Checked with a test kit chlorine levels show at or above 0.5mg/L.
Excess Chlorine brought about by chlorinated mains supply. All mains water for use with fish should be checked BEFORE use with a Chlorine test kit and if necessary treated before fish are put into the water.
Susceptibility varies among species. Usually more than .5mg/L can give problems to sensitive species. Eliminate Chlorine quickly and most fish will recover, if exposure was not too long.