author(s)
Kumawat Rajkumar, ML Ojha, VP Saini and SK Sharma

abstract
The present study was conducted to assess the impact of water hardness on survival and growth of (Labeo rohita) fry. In each tank 100 fry ware introduced and the experiment was run in triplicate for a period of 28 days. The selected levels of hardness had significant impact on fish growth with a highest weight gain (2.019±0.036g) was observed in T₄ (Hardness 150 mg/l) and lowest T₅ (1.189±0.054g). The highest per cent weight gain (86.14%) was T₄ (Hardness 150 mg/l) while the lowest (49.66%) being in T₅. However, the highest gain in length (18.93±1.18 mm) was in T₄ and lowest (13.99±0.46 mm) in T₅ and per cent length gain was highest (130.33%) in T₄ and lowest (98.67%) in T5. Further the highest survival was in T4 (95.33%) and lowest (90.00%) in T5. Result of this study clearly indicated higher weight gain (2.019g), weight gain per cent (86.14%), length gain (18.93mm), length gain per cent (130.33%) and survival (95.33%) in the hardness level 150 mg/l. On the basis of these results a hardness level of 150 mg/l is recommended for Labeo rohita under local environmental conditions.