A new species of histozois myxosporidean,Kudoa tetraspora, infecting the tissue around the optic lobes of a fish,Mugil cephalus is, described. This is the second report of a species ofKudoa from India and the second in the world which establishes around the brain. The cysts range varies from 0·3–1·5 mm in diameter and are attached superficially to the tissue around the optic lobes. The spores are quadrate in polar view each measuring 9·0×9·0 μm and contains 4 polar capsules. The polar filaments are thick and each measures 10·0–12·0 μm in length. The spores are characteristically arranged in groups of four for which the name ‘tetraspora’ is proposed.