This study is examing the effectiveness of marine fish waste POC as a substitute for commercial nutrition in the growth and yield of pakcoy (Brassica rapa L .) in the axis hydroponic system, and to obtain the right nutritional formulation in the marine fish waste POC by setting the EC (electrical conductivity). The study was conducted at the Green House of the Faculty of Agriculture, University Of Muhammadiyah Yogyakarta in December – February 2019.This research was done in experimental method, arranged in single factor of completed randomized design (CRD). The treatment were : treatment P1 : AB Mix nutrient concentrations of 1,40 mS/cm, treatment P2 : marine fish waste POC concentrations of 0,50 mS/cm, treatment P3 : marine fish waste POC concentrations of 0.75 mS/cm, treatment P4 : marine fish waste POC concentrations of 1,0 mS/cm, and treatment P5 : marine fish waste POC concentrations of 1,25 mS/cm. Each treatment was repeat 3 times so that there are 15 experimental units consisting of 6 plant samples, three victim plants and three sample plants so total 90 plants. The results show that the nutrient administration of marine fish waste POC can be used as a substitute for commercial nutritions with concentrations of EC values of 1,0 mS/cm.