The influence of feeding frequency on the growth, physiology, and reproductive biology of the <i>Archocentrus nigrofasciatus var. × Mikrogeophagus ramirezi</i> hybrid

The study investigated the effects of feeding frequency on the growth and reproductive performance of the ornamental hybrid fish Archocentrus nigrofasciatus var. × Mikrogeophagus ramirezi . Three feeding treatments were used in a 56-day feeding trial (G2:2 times/day, G3:3 times/day, G4:4 times/day). Growth performance, reproductive traits, physiological and biochemical indicators, and water quality parameters were assessed. Significant differences were found in weight, body length, and body height among the three groups (P &lt; 0.05), while the survival rate did not differ significantly (P &gt; 0.05). Testicular and ovarian development followed the same pattern: G3 showed the highest maturity, followed by G2, with G4 the lowest. Average fecundity, fertilization rate, and hatching rate of females in G3 and G4 were significantly higher than in G2 (P &lt; 0.05). Larvae in G3 also showed substantially improved growth seven days post-hatching. Regarding water quality, there was no significant difference in the pH among the groups (P &gt; 0.05). Ammonia-nitrogen levels increased with feeding frequency. Digestive enzyme activities peaked in G3. CAT activity decreased as feeding frequency increased, while T-SOD and T-AOC levels in G3 and G4 were significantly higher than in G2 (P &lt; 0.05). The results indicate that three times feeding frequency is best for growth and reproductive performance in Archocentrus nigrofasciatus var. × M. ramirezi . This feeding regime supports improved gonadal development, better offspring survival and early growth, and maintains a relatively high growth rate. These findings provide valuable theoretical and practical guidance for breeding programs of this hybrid fish species.