Search

The use of biofloc technology has positive effects on the quality of water and utilization of feed through the recycling microbial protein during the culture of commercially important finfishes. This culture technology is also used in the rearing of ornamental fish to address limitations on land space and water use as well to minimize the impacts of wastewater discharge. Therefore, the current study evaluated the utilization of plant wastes in the production of biofloc for the ornamental fish culture. A 30-day trial was conducted to evaluate the effects of using sweetpotato, Ipomoea batatas wastes in biofloc production for the rearing of molly, Poecilia sp. The effects on growth, water quality and bacterial population in the water were evaluated. Triplicate tanks of water supplemented with dried sweetpotato wastes (biofloc treatment) at a C:N ratio of 10 and the non-biofloc group were stocked with mixed-sex juveniles of molly at a density of 3 fish per liter and reared for 30 days. Significant differences were observed in water quality parameters particularly lower concentrations of ammonia and nitrate in the biofloc group. Growth parameters showed better growth and lower feed conversion rate in the biofloc group. Higher bacterial counts were also observed in the biofloc group than in the control. The current study showed that sweet potato wastes could be used in the production of biofloc during the rearing of ornamental fish and the presence of bioflocs can increase bacterial population in the water resulting in the recycling of nutrients that could lead towards improving water quality and enhancing fish growth.

The tropical ornamental fish industry requires the stock to be reared in captivity before being sold; thus, exposing them to various handling- and transport-related stressors. A number of commercially available anesthetics are used during fish husbandry procedures, but these products are expensive and not readily available to small-scale ornamental fish operators. The use of sodium bicarbonate as an inexpensive anesthetic during routine husbandry activities in molly, Poecilia sp., a freshwater ornamental fish was assessed in terms of its effect on sedation, recovery and survival post-exposure in three independent experimental runs. Juvenile molly were exposed to sodium bicarbonate at a concentration of 100 g L−1 and the time to sedation and recovery were monitored. It took longer for the fish to be fully sedated than their recovery. Survival of the fish a week post-exposure ranged 40-60%. Simulated transport of fish for 6 hrs in water containing 1 g L−1 of sodium bicarbonate showed survival ranging 70-100% a week after transport. These findings demonstrated that sodium bicarbonate could be potentially used as a low-cost anesthetic during handling and short-term transport of ornamental fish. Future studies shall focus on discovering the underlying physiological mechanisms in fish following sedation with this chemical.