Contested Paradigm in Raising Zebrafish (Danio rerio).

Area of Science:

• Aquaculture and Aquatic Animal Science
• Developmental Biology
• Fish Biology

Background:

• Traditional zebrafish (Danio rerio) rearing relies on freshwater, diurnal light cycles, moderate feed density, and high visibility.
• These conditions are presumed necessary for optimal larval and juvenile development, growth, and survival.

Purpose of the Study:

• To challenge conventional zebrafish rearing protocols by implementing constant light, increased salinity, and continuous feeding.
• To evaluate the impact of these modified conditions on zebrafish behavior, growth, survival, and reproductive performance.

Main Methods:

• Zebrafish were reared under constant light (46-48 days postfertilization [dpf]) in saline water (1.8-2.1 ppt) with continuous feeding.
• High initial stocking density (100 larvae/L) and high rotifer densities (200-400/mL) were used, followed by a switch to rotifers or brine shrimp (Artemia) nauplii.
• Adult performance, generation time, and fertilization rates were assessed under these novel conditions.

Main Results:

• Zebrafish exhibited no negative effects on behavior, growth, or survival under constant illumination with continuous food availability.
• Adult zebrafish fed rotifers followed by Artemia nauplii showed superior performance, with weights of 250 ± 29 mg (males) and 430 ± 5 mg (females) at 42 dpf.
• The modified rearing conditions resulted in the shortest recorded generation time (43-45 dpf) and high fertilization rates (80.3%-94%).

Conclusions:

• Constant light, increased salinity, and continuous feeding are viable alternatives to traditional zebrafish rearing methods.
• These optimized conditions promote rapid growth, high survival, and efficient reproduction in zebrafish.
• The findings offer a paradigm shift in zebrafish aquaculture and research, enabling faster life cycle completion and potentially higher yields.