author(s)
Shahida Parveen, Ram Bharose and Dharam Singh

abstract
Channa punctatus is the most common fish found in Indian rivers and water bodies. The present study was conducted to investigate the dilution effect of tannery waste water on the activity of serum LDH enzyme of the Indian freshwater fish Channa punctatus. The effect was observed based on the result of chronic toxicity and comparison of control with experimental groups. Tannery wastewater causes cellular hypoxia creating anaerobic condition and cellular damage. Investigation showed significant increase in LDH level with increase in concentration of tannery wastewater (5%, 10%, 15% and 20%TWW) i.e. 31.66 and 29.57 IU/L in 5% concentration to 50.64 and 48.25 IU/L in 20% concentration at both site 1 and 2 respectively and also with increase in exposure period in all concentrations from 15^th to 45^th days. The results indicate the effect of tannery wastewater stress at the organ level of fish and represent a valuable tool in biological monitoring.