The efficiency of Psidium guajava was studied to illustrate the reduction of ferric nitrilotriacetate (Fe-NTA) toxicity in Puntius altus via the histopathology analysis. The fish (n = 40) were randomly divided into four groups. Each fish was transferred to each aquarium as follows: G1 and G2 were obtained normal fish food; G3 and G4 were obtained guava leaf extract 60 mg g-1 fish food. After 28 days dietary supplement, fish in G2 and G4 were injected intraperitoneal of 9 mg Fe kg-1 b.wt. Twenty-four hour after injection, lesions were especially most evident in the G2. The gills were observed epithelial lifting, lamellar cell hyperplasia. Blood congestion was seen in sinusoids and hepatocytes necroses were also observed. Renal tubular swelling and necrosis were seen. Some areas were found hemosiderin pigment accumulation. Fish with guava pre-treatment (G4) showed slightly alteration when compare those of G2 group. The results suggested that P. guajava leaf extract pre-obtained may play an important role in the reduction of Fe-NTA toxicity in fish.