In the present investigations a common pond murrel, C. punctata was selected
as a test animal because it is commonly found in abundance in fresh water bodies,
its sensitivity and suitable karyotype consisting of small number (2n = 32) of large
sized chromosomes. Live specimens of C. punctata taken from local lentic habitat
were acclimatized to laboratory conditions (hardness 74.6 as CaCO3 mg/L, alkalinity
76.35 as CaCO3 mg/L, DO 6.91 mg/L, COD 62.5 mg/L, chloride 146.4 mg/L, TDS
228.33 mg/L, pH 7.02 and temperature 28 ◦C) in 100 L well aerated glass aquaria
(100 cm × 40 cm × 40 cm) for 15 days.