The different strains of the climbing perch, Anabas testudineus are found in different countries. Being different in origin, Thai strain possesses some biological differences from the native one of Bangladesh. A comparative study of some biological aspects was carried out between them. Strains being genetically slightly differentiated, they readily interbreed if they are brought into the same habitat conditions. Attempting on artificial hybridization may result in hybrid vigor to produce better offspring for controlled aquaculture. Being conspecific, on the other hand, their mating with the local population in the nature may not be unexpected, if the exotic ones escape to the natural water bodies, which might have a conservation concern for the native climbing perch in open waters. All these biological and genetic stuffs have been addressed in this book.