author(s)
Subramani Sathish, Pushparaj Chidambaram, Arumugam Uma and Pandiyan Yuvarajan

abstract
A six month field study was conducted to investigate the incidence of parasitic infection and its interactive factors in the Tilapia farms at Tamil Nadu. About twenty tilapia farms were selected from the Thiruvarur, Krishnagiri, Nagapattinam and Thanjavur districts. Culture water and fish samples were collected from the each selected farms and transported to the laboratory for parasite identification. The protozoan parasites (Tetrahymena sp., Trichodina sp., Epistylis sp., and Chilodonella sp), monogenean trematode (Dactylogyrus sp.) and crustacean parasite (Argulus sp.) were identified from twenty farm samples. Among that, protozoan parasitic infection was found to be maximum (69%) followed by monogeneans (26%) and crustaceans parasites (5%). High stocking, poor water quality and poor feeding practices influenced the parasitic incidence. Farmers has been using the commercial antiparasitic agents to control the parasitic infection in the 18 farms. The Clinar (Cypermethrin) antiparasitic agent was mostly utilized by farmers followed by Doom (Dichlorovus-76% E.C), Nuvan (Dichlorvustech.83.0%, 0%) and Butox Vet (Deltamethrin 1.25%). The present study found that, the tilapia farms of Tamil Nadu has mostly infected with protozoan parasites due to the poor biosecurity. Hence, farmers should improve the biosecurity to minimize the disease and avoid the synthetic chemicals for environment safety.