Environmental conditions of egg deposition sites of endangered wild medaka, Oryzias latipes, were investigated in a pond on the Nara Campus of Kindai University and in the Nogawa River in Tokyo in order to obtain basic information for conservation of wild medaka. Eggs were deposited on the roots of land plants that extended into the water, green algae, and aquatic moss as substrates. Deposited eggs were observed in shallow water areas at the depth of 1 to 5 cm.
