Gliding bacteria M165 was isolated from roted gill of grass carp(Ctenopharvngodon idellus). It is capable of infections and even causing death to thefish as well as to other pond fishes through multi-infections in water. The biologicalcharacteristics of M155 resembles Myxococcus piscisola, but it could not quickly producemicrospore by Dworkin's method. DNA (G+C) of the bacteria is 35.3%. Quite dif-ferent from Myxococcus, it should belong to Flexibacter columnaris.