Akpomughe E.¹ , Awhefeada O.K.¹ , Mukoro J.E.² , Okpu P.N.³

1 Department of Fisheries and Aquaculture, Delta State University, Abraka, Nigeria
2 Department of Animal Production, Southern Delta University, Ozoro, Nigeria
3 Department of Entrepreneurship Development, Southern Delta University, Ozoro, Nigeria
Author    Correspondence author
International Journal of Aquaculture, 2026, Vol. 16, No. 2   
Received: 15 Jan., 2026    Accepted: 13 Mar., 2026    Published: 31 Mar., 2026

This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

This study investigated the anesthetic efficacy and safety of aqueous leaf extracts of Citrus sinensis, Citrus aurantium, and Citrus limon in Nile tilapia (Oreochromis niloticus) and African catfish (Clarias gariepinus) under controlled immersion conditions. Qualitative phytochemical screening revealed distinct variation in bioactive constituents among the extracts. Experimental exposure was conducted at concentrations ranging from 1 000 to 4 000 mg L⁻¹, and responses were evaluated using induction time, recovery time, survival, behavioural indicators, and flesh quality parameters. Anesthetic effects were concentration dependent in both species. Citrus sinensis produced mild to moderate sedation across all tested concentrations, with no mortality recorded even at 4 000 mg L⁻¹, indicating a wide safety margin, and 3 000 mg L⁻¹ was identified as the highest effective concentration for routine handling. In contrast, Citrus aurantium and Citrus limon induced deeper anesthetic states at lower concentrations but resulted in 100 percent mortality at 4000 mg L⁻¹ in both species. Fish exposed to Citrus sinensis exhibited more favourable post exposure welfare indicators, including faster recovery and earlier resumption of feeding, whereas the other extracts were associated with delayed recovery and behavioural impairment. These findings indicate that Citrus sinensis appears more compatible with short term handling welfare and represents a practical and cost effective botanical anesthetic for freshwater aquaculture.

Fish anesthesia; Citrus leaf extracts; Clarias gariepinus; Oreochromis niloticus; Handling stress; Aquaculture welfare