At present, fish farmers are searching for cheaper alternatives of fish feed. Here, we assess the suitability of pea meal (Pisum sativum), with and without enzyme (phytase)/citric acid supplementation, as a feed for Nile tilapia (Oreochromis niloticus). After 90 days, we recorded a significant increase in total length, weight, and weight gain in groups fed 60% pea meal, both with and without citric acid and/or phytase. The number of erythrocytes dropped significantly against controls in all 60% pea meal groups, while leucocytes were higher in all groups fed 30 and 60% pea meal. No significant changes were recorded in plasma biochemical parameters, except for aspartate aminotransferase, triacylglycerol, and chlorine which were significantly lower, and contrarily calcium, sodium and blood plasma iron were significantly higher, than in controls in all 60% groups. Consequently, feed with 30 and 60% pea meal is suitable for feeding farmed tilapia and enrichment with phytase and citric acid is recommended. The results of the study show that peas can be a new source of protein in intensive fish aquaculture nutrition. It therefore has the potential to partially replace soybeans in aqua feeds. Peas may also have the advantage of being a crop easy to grow, widespread throughout the world, and not genetically modified.