Abstract
Diagnosis is one of the most important steps for prevention of disease. In the present study, we have isolated bacteria from the muscles of theabdominal infected area of diseased fish-Catlacatla, whichis the fastest growing Indian major carp and an important freshwater fish in Asian countries. On the basis of primary and secondary biochemical test, it was confirmed that Edwardsilatarda, Aeromonashydrophila and Vibrio cholera are frequently present. DNA was isolated and amplified with help of PCR and then RFLP was performed, which showed all the three bacterial isolates were pathogenic in nature on the basis of 350bp band pattern. Cell lines designed as C. catla blood monocyte was developed from adherent peripheral fish are one of the healthiest and low calorie nutrient rich food sources. Partial sequencing, amplification and alignment of fragments of two mitochondrial genes 16S rRNA and CO1 confirmed that the developed cell line originated from C. catla. This cell line could be successfully employed for cytotoxicity assays as revealed by uptake of neutral red. This cell line can be auseful tool to study the role of macrophages in teleost immune response and development of markers for macrophages.