Abstract: A new suctorian species,(Trichophrya bivacuola,sp.nov.),parasitized on the gill of Megalobrama amblycephala has been described.The living organism is transparent to yellowish in colour,and oviform to elongated ellipsoid in front view,with a somewhat flat body. It is od or sausage-like in lateral view and usually creeps on the lamellae of gill filament. Many small inconspicuous granules may exist within the pellicle of this suctorian.There is a bundle of tentacles at the anterior end of the body,and the number of tentacles usually varies from 4 to 8 and was 23 in one case.In contrac ed condition,part of the tentacle may show 8 to 11 spiral folds.T.bivacuola has two contractile vacuoles,which are about 7 μm in maximum diameter and located parallely near the anterior part of the body keeping about 10 μm apart in distance.They contract alternatel in living body.The macronucleus is ellipsoid or short rod-like with many coarse granular chromatin.Only one spherical micronucleus is detected.The adult or immature suctorians have no stalk.The young ciliophora have a wide ciliary band which is 6—7μm in width and consists of 7 to 11 ciliary rows.