Biogas-plant effluent as an organic fertiliser in fish polyculture

Biogas-plant effluent collected from a KVIC model biogas-plant fed on cattle waste was utilised in fish polyculture. Biogas-plant effluent was applied at 0·15% concentration at 3-day intervals. The growth rate of Labeo rohita was 4·52 ±0 ·75 g fish^?1 day^?1, of Cirrhina mrigala 3·36 ± 0·48 g fish^? day^?1 and of Cyprinus carpio was 1·82 ± 0·41 g fish^?1 day^?1. Total fish production was 13·44 ± 0·77 kg 0·002 ha^?1 year^?1 (6653 kg ha^?1 year^?1) without any supplementary fish-feed.