The present study embodies description of Chilodonella hexasticha1,10 isolated from edible as well as ornamental fish Botia rostrata from Dikrong river Arunachal Pradesh, India. This ciliate is 48.25-56.49(50.38±1.57) µm in length and 40.44-48.82(43.88±2.08)µm in width.Taxonomic description of this species have been depicted as per the norms of Lom 1958.2 This communication also holds scanning electron microscopic picture of C. hexasticha for a detailed and clear illustration of its morphology along with seasonal prevalence, morphometric details. In conjunction with a detailed morphomatric comparison of the present species with previously reported species has been done. This data plays a crucial role in the fishery industry as it causes severe disease chilodonellosis, causing mass mortality of fishes. Also it contains the first record of chilodonellid infestation of ornamental fish in Arunachal Pradesh, India. Context: Though a lot of studies have been done on fish parasites in India but there is relative paucity in case of infestation of ornamental fish parasites on fish fauna of North East India. So keeping this in mind a survey had been done from March 2019 to march 2020 to examine parasitic infection on Botia fish along with a morphometric data. Aim: The objective of the study is to dessiminate adequate knowledge regarding the genus Chilodonella. This study has also been compiled some published accounts regarding this genera in order to prepare a little but significant informations that is a vital point in the world of taxonomy. Setting and Design: All authors had participated in the study design. Sample collection and total work has been done by first author and manuscript writing was done by second author. Corresponding author participated planning and supervision of the work. All authors had critically read and approved of the final manuscript Materials and Methods: Sampling: A survey has been accomplished in the middle of March 2019-March 2020. Collection of host fishes had been done from Dikrong River of Arunachal Pradesh. For primary study live fishes were luged to the laboratory of the Department of Zoology, Rajib Gandhi University, Arunachal Pradesh, India. In Parasitology Laboratory, Department of Zoology, Kalyani University, West Bengal identification has been done. Parasitological Examination: A total of 537 number fishes have been minutely observed for detection For ectoparasitic infestation. Body of host fishes mainly Skin, gill and fins were intensively examined. Isolation of Pathogens: Months of the calendar year the host fishes were collocated extensively. Affected fishes were isolated on the verge of signs of parasitic infestation. Thin smears of gill, fin and skin of host fish had been made on grease free slides. After that slides were dried in air and impregnated for 10 min in 2% aqueous AgNo3 solution (Klein 1958)15, washed (distilled water), and placed under ultraviolet ray for 25– 30 min. Using Olympus BX 43F