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This study contributes data on haematological and biochemical parameters of African catfish, Clarias gariepinus. It employed a 3 ? 2 factorial design with three ponds of different water depth (0.5, 1 and 1.5 m) and two types of feed (floating and sinking). Twelve earthen ponds (1 m x 2 m) were stocked with 16 fingerlings catfish each (mean weight ~100g) and their blood parameters were monitored over 12 weeks. Differences in hematological parameters related to water depth were mostly significant, and better results were recorded in fish reared in shallower water ponds. Feed type showed improved hematological parameters with using of sinking diet. Most biochemical parameters showed significant differences in pond waters depth and feed type with better results coincided with rearing fish in shallower water depth and with sinking feed. Conclusively, culturing Catfish in shallow ponds (0.5 m) and use of sinking feed improve physiological response and health condition.

African catfish (Clarias gariepinus) has been growing in popularity as a culture species globally. Although considerable research has been carried out on this species’ feeding preferences, no research has been carried out on optimum water level for growth. This is particularly surprising given this species' benthic nature. This study assessed the effect of different combinations of water levels and types of feed on the growth performance of African catfish. The study employed a 3 × 2 factorial design with three ponds of different water levels (0.5, 1 and 1.5 m) and two types of feeds (floating and sinking). Twelve earthen ponds (1 × 2 m) were each stocked with 16 catfish fingerlings (mean weight ~100 g), and their growth was monitored for 12 weeks. The fish cultured in the shallowest water grew significantly faster than those cultured in the deepest ponds. At the same time, fish cultured in the shallowest ponds had the lowest feed intake rates and consequently the lowest feed conversion ratios. Catfish fed sinking pellets grew faster than those fed floating pellets although the difference was not significant. There was no significant interaction between pond water depth and feed type. The results of this study suggest that the growth and feeding efficiency of C. gariepinus can be optimized by culturing in fairly shallow ponds (0.5 m).

This study was aimed to explore differences between day and night feeding of farmed European eels ( Anguilla anguilla ) on: (1) the growth and feeding behaviour of eels; and (2) the subsequent impact on the quality of the culture water. A 30 day field experiment was conducted in which 40 European eels (186.4 ± 9.26 g) were arbitrarily allocated into two replicate concrete ponds (200 x 100 x 125cm) that were divided into two treatment groups, one receiving feed by day (DF) and the other receiving feed at night (NF). Results revealed a significant improvement in eel's growth performance (larger final weight and faster growth) of the fish that were fed by night (NF). Moreover, feeding behaviour was also improved in the NF group with a significantly shorter latency to start feeding and shorter feeding duration. As a consequence of improved feeding behaviour, more favourable water quality conditions (higher dissolved oxygen concentrations and lower ammonia concentrations) were observed in the NF group. In conclusion, feeding eels by night could considerably enhance the culturing of eels by promoting enhanced growth and feeding behavior, and simultaneously improving water quality. Key words : feeding regime; European eel; behaviour; nocturnal feeding; growth; performance Â