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usually results in high mortality. Mass mortality were reported in larval sea bass Lates calcarifer in a hatcheryassociated with clinical signs such as abnormal swimming behavior, pale-gray discoloration of the bodyHistological investigations in moribund fish revealed marked vacuolation in the retina and brain. Cytopathic effects(CPE) were observed in SSN-1 cells inoculated with the tissue filtrate of affected sea bassControl methods are disinfection of fertilized eggs by ozonized water. Disinfection of water, feeds, ponds, facilitiesand tools. Take off feces and dead fish from the ponds frequent.Koi herpesvirus disease (KHVD)Causative agent of this disease is pathogen type: DNA herpes-like virus in the family Herpesviridae name: Koiherpesvirus (KHV) (170 – 230 nm). Common carp, Koi carp (Cyprinus carpio) is the specific host for this virus.KHV first reported in Israel and USA in 1998 and after that it was pandemic to many countries world wild.Clinical signs of this disease are hemorrhagic lesion on skin and focal rotten gills with excess mucus excretion.Infected fish will gather at the water inlet.Diagnosis techniques are virus isolation and confirmed by PCR of the viral isolates. Even without isolation of thevirus PCR can be used to detect the DNA of virus in fresh, infected tissues.Fungal diseaseEpizootic Ulcerative Syndrome (EUS)The case definition of EUS is “a seasonal epizootic condition of freshwater and estuarine warm water fish ofcomplex infectious etiology characterized by the presence of invasive Aphanomyces infection and necrotizingulcerative lesions typically leading to a granulomatous response” (ODA, 1994). The synonyms of this disease areEUS-related Aphanomyces (ERA) Philippines, Red Spot Disease (RSD): Australia, Mycotic Granulomatosis (MG):Japan, Ulcerative Mycosis (UM): East Coast USA.The causative agent of this disease is a fungus name Aphanomyces invadans. The clinical signs of disease arenormally start with mass mortality of wild and cultured fish in a new location. Infected fish show small red areas orulcers on the body, deep hemorrhagic ulcers with fungal mycelium on surface, skull erosion, loss of eyes and partof the brain.This disease can be confirmed by the isolation of Aphanomyces invadans fungus and the specific mycoticgranulomas found in the histological sections of various tissues of infected fish with some special stains; Grocott’s,Periodic Acid Schiff’s (PAS) or UV Tech.Prevention and controlKeep eyes on the health of the wild fish during the cool season. If the EUS spread to the fish pond, stop waterexchange, remove the moribund and death fish. Improve water quality using agriculture lime or hydrate lime. Saltcan be applied to minimize the toxic of H 2 SRecommendationAn accurate disease diagnosis is necessary for diseases in finfish management, prevention and treatment.www.oie.int and www.enaca.org are good sources of aquatic animal disease diagnosis techniques.60