Capillaria is a class of parasitic nematodes that are commonly found in fish as intermediate hosts to reach their final hosts, which include humans. The present study was performed to analyze the prevalence of Capillaria sp. isolated from red tilapia fish (Oreochromis sp.) in Egypt.  Fish were randomly collected alive or freshly dead, from May to November 2020 from a fish farm in Suez Governorate, Egypt.  A total number of 190 freshwater fish with average weight and length of 26±0.35 g, and 11±0.25 cm, respectively were examined. The average body mass of infested males and females were 24±0.41 and 28±0.5 g, respectively, while the total length for both of them was 9.2±0.25 and 13±0.2 cm, respectively. Hematological and biochemical parameters were recorded in the infested fish. Also, a histopathological examination of different organs of infested fish was done.  Naturally infested fish revealed pathognomonic clinical signs such as excess mucus secretions, the opening of the mouth and in some cases, appeared exophthalmia. A postmortem examination revealed an empty, shrinking stomach, as well as the pale coloration of the internal organs. The total infestation prevalence was 41.1% with Capillariasis. Males showed more infestations (65.38 %) than females (34.62%). Regarding hematological and biochemical parameters, the study results showed highly significant differences (P≤ 0.05) between infested and non-infested fish. Histopathological sections of the liver, spleen and intestine of fish indicated that there were moderate abnormalities that occurred due to infestations.