Artemia spp. (brine shrimp) nauplii are widely used in the aquaculture of many larval and juvenile fishes both marine and freshwater and provide essential nutrients during the early developmental stages of many aquatic species. Most freshwater ornamental fish larvae are typically fed live Artemia as their first food source until they grow large enough to transition to alternative feeds. This initial feeding period typically lasts 1 – 4 weeks, depending on the species’ growth and developmental rate. As larvae mature, they are gradually weaned onto other feeds such as crushed flake food, pellets, or other suitable live or frozen foods. Considering the high cost of Artemia cysts, variable supply, and the dependence of many cultured species during the larval stage, this study aims to evaluate commercially available liquid diets as cost-effective alternatives for Artemia replacement. Specifically, we assessed the inclusion of these liquid diets for larval feeding in three freshwater ornamental fish species: rainbow shark (Epalzeorhynchos frenatum), tiger barb (Puntius tetrazona), and bronze corydoras (Corydoras aeneus).
Three trials are being conducted to evaluate two commercially available liquid diet brands as Artemia replacements, and to identify the most suitable diet for optimizing growth and survival of each species. Each trial will be conducted in 25 3L tanks, with five replicates per treatment. During the experimental period, larvae will be fed one of five dietary treatments: 1) 100% Artemia nauplii reference diet (200 nauplii/L), 2) 100% Cargill Liqualife M-PL (200 particles/L), 3) 100% Zeigler EZ Artemia Ultra size 2 (200 particles/L), 4) 50% Cargill Liqualife M-PL / 50% Artemia nauplii (100 particles/L + 100 nauplii/L), 5) 50% Zeigler EZ Artemia Ultra size 2 / 50% Artemia nauplii (100 particles/L + 100 nauplii/L). Water quality parameters, including ammonia, nitrite, nitrate, hardness, and alkalinity, will be measured on the first and last day of the trials, and temperature, dissolved oxygen, and pH will be monitored daily.
Preliminary results for E. frenatum showed that treatments combining liquid diets with Artemia produced larvae with total lengths statistically similar to the control (6.46 mm), with average lengths ranging from 5.94 mm to 6.21 mm. In contrast, larvae fed exclusively with liquid diets had shorter total lengths, ranging from 5.13 mm to 5.24 mm. In terms of survival, the control treatment exhibited the highest survival rate (48%), followed by the treatments combining liquid diets with Artemia (33% and 34%), while the exclusive liquid diet treatments resulted in significantly lower survival rates (10% and 14%). The remaining experiments are ongoing, and the complete results will be presented at the conference. These results are critical for the freshwater ornamental aquaculture producer as they demonstrate a cost-effective alternative to Artemia nauplii, potentially reducing reliance on live feed and lowering production costs. Further research will focus on optimizing the inclusion rate of liquid diets and developing a weaning protocol to determine the optimal timing for transitioning from live feed to liquid diets.