It was observed the algal bodies were always larger in the lower side than in the upper side, and this ecological fluctuation was experimentally ascertained by the translocation of the algae from the upper to the lower side. The action in vise versa, from the lower to the upper belt, checked the growth of the alga, but in this case, the treatment was effective to eliminate the harmful algae to the Gloiopeltis. Such translocation in the fittest time seems to be useful for the cultivating technique of the Gloiopeltis.