Water reservoirs are very valuable floristic sites in Poland. Among them, the most im-portant for preservation of biodiversity of flora are fishponds. The long-term process of human pressure on habitats of this type caused disturbance of their biological balance. Changes in the water regime, industrial development and chemisation of agriculture, especially in the period of last two centuries, led to systematic disappearance of localities of many plant species and plant communities. Gnaphalio uliginosi-Eleocharitetum acicularis Passarge 1999, of Isoëto-Nanojuncetea class Br.-Bl. et Tx. 1943, was firstly described in Germany. This association grows on sandy or sandy-gravely banks of rivers and in old river beds. In Poland, Gnaphalio uliginosi-Eleocharitetum acicularis has not been found so far. The patches of this type have been described many times, but otherwise classified acording to syntakxonomical system. During current vegetation research the association Gnaphalio uliginosi-Eleocharitetum acicularis was found in seven fish-breeding ponds in south-western Poland. Fieldworks were conducted in 2000–2016.