In 2021, pak choi production in Indonesia was 727.47 Mg, marking an increase of 8.2% compared to the 2020 production, which was 667.47 Mg. Therefore, there is a clear need for cultivation improvement, particularly through the implementation of organic fertilisers. This study aimed to investigate the impact of liquid organic fertiliser (LOF) derived from fish waste and duck manure on the growth and yield of the pak choi plant ( Brassica rapa. L. var. Nauli F1). A randomised block design factorial was used with two factors and three replications. The first factor considered was LOF from fish waste, comprising three levels (LOF ₀ = control, LOF ₁ = 25 cm ³∙dm ^–3 of water, and LOF2 = 50 cm ³∙dm ^–3 of water). The second factor focused on duck manure fertiliser (DMF) and involved four levels (DMF ₀ = control, DMF ₁ = 3.7 kg∙plot ^–1, DMF ₂ = 5.55 kg∙plot ^–1, and DMF ₃ = 7.4 kg∙plot ^–1). The results showed that the application of LOF from fish waste positively influenced the growth and yield of pak choi, with the most effective treatment observed in LOF1 (25 cm ³∙dm ^–3 of water). However, the application of DMF did not yield a significant difference in its effect on the growth and yield of the pak choi plant. The control treatment (DMF ₀) reported comparable results and the combination of LOF from fish waste and DMF did not show a significant effect, with the most favourable findings observed in the LOF ₂DMF ₀ treatment (50 cm ³∙dm ^–3 and control).