Fish feeds play a major role in aquaculture production; however, they cause a great challenge to fish farming as they contribute up to 70% of aquaculture's total financial inputs. Red earthworm meal (REWM) which was the by-product of water hyacinth (Eichornia crappies Solms) based vermicompost was tested to replace fishmeal in diets of Nile tilapia (Oreochromis niloticus) fingerlings as an alternative protein source. The replacement levels were within five treatments: T00%, T25%, T50%, T75% and T100%, which were designated as treatment T1, T2, T3, T4 and T5 respectively. A total of 225 Nile tilapia fingerlings at an average weight and length of 7.39±0.34g and 6.13±0.55cm respectively in the triplicate group were used for the experiment. Fingerlings were fed at 30 % of crude protein level of formulated diet two times per day (8:00 am-9:00 am), and (4:00 pm-5:00 pm) within five percent of their body weight for ninety days. Sixty percent of the fish were sampled using a scoop net before feeding within fortnight intervals, and then weighed and was measured. In the meantime, the amount of feed was adjusted based on the newly recorded weight. SPSS version (20) software was applied for the analysis part and Tukey hoc test were used to the mean comparison between treatments. Fingerlings maintained high specific growth rate and mean weight gain at T3 (50% of REWM) and it was statically significant (F4, 10 =4.329, P=0.027 and F4, 10 =9.538, P=0.02 respectively). Moreover there were no statically significant in feed conversion ratio (F4, 10=1.084, P=0.415) of which the least feed conversion ratio were revealed at T3 and the highest was at T1. The study revealed that T3 scored better growth performance with more gross income than others, hence the combination of half protein source from fishmeal and half from earthworm meal is recommended to formulate best feed for Nile tilapia (O. niloticus) fingerlings.