Investigation of microworms (Panagrellus redivivus) as an alternative live feed for Pethia conchonius larvae

This study evaluates the growth performance and survival rate of Pethia conchonius (Hamilton 1822) larvae fed microworms (Panagrellus redivivus, Linné 1767) compared with Artemia salina nauplii and granular feed. Fifteen-day old larvae that had completed yolk-sac absorption and an initial Artemia-based prefeeding period (initial mean weight: 0.010 g; mean length: 0.657 cm) were randomly divided into four groups (A. salina nauplii (Group A; control), P. redivivus (Group M), granular feed (Group Y), and P. redivivus + granular feed (Group M+Y). Each group was designed with three replicates; live body weight, total length, specific growth rate (SGR), and condition factor were measured at 9-day intervals for a 36-day feeding period. At the end of the experiment, the survival rate remained above 95% in all groups; no statistically significant differences were found between the groups (p > 0.05). The highest live weight was obtained in Group M+Y (0.0948 ± 0.001 g); this value was higher than in the artemia control group (0.0748 ± 0.001 g). Length growth also followed a parallel pattern; Group M+Y reached the highest total length with 1.424 ± 0.008 cm. In the first nine days, Group M+Y and Group A exhibited statistically equivalent SGR (10.171 ± 0.259 and 10.354 ± 0.456 %/day, respectively; p > 0.05); from day 18 onwards, Group M+Y surpassed all other groups. The difference between Group M and Group Y did not maintain its statistical significance throughout the experiment (p > 0.05). These findings reveal that applying a co-feeding protocol of microworms and 150–300 µm granular feed from day 15 onwards in P. conchonius larvae can provide higher growth performance and remove the need for continued Artemia feeding beyond day fifteen. P. redivivus is recommended as a low-cost and sustainable live-feed alternative for the post-larval stage of ornamental fish.