Several milkfish (Chanos chanos) juveniles polycultured with the Indian prawn (Penaeus indicus) in earthen ponds at the Leganes Station of the Aquaculture Department, SEAFDEC, Philippines, manifested eye abnormalities. Signs observed varied from unilateral and bilateral opaque eye coverings/eye balls, exophthalmia and hemorrhagic eyes. A vibrio was predominantly isolated from the opaque eye coverings and eye balls, and it was proved pathogenic to milkfish, Japanese eel (Anguilla japonica) and mouse by injection experiments. The opaqueness of eye coverings of milkfish was likewise reproduced by a combination of injury and contact with the pathogen. The bacterium, though seemingly closely related to Vibrio parahaemolyticus or V. alginolyticus, was not identified to any known Vibrio species