Parasitic fish diseases have a negative impact on fish production, it may result in direct fish mortality, reduction in fish growth and fecundity it also increase the susceptibility to other diseases, this book deals with a wide range of parasitic diseases affecting Clarias gariepinus including microsporidia, Myxobolus, henneguya, trypanosome, digenia (encysted metacercariae), flukes, nematodes and cestodes.