(physa acuta) gastropod mollusk, an invader in the south of ukraine on a leaf of a floating plant

mollusk gastropod invertebrates freshwater snail pond molluscs physa marmorata underwater physidae snails bladder lymnaeoidea pulmonate lymnaea stagnalis aquarium physella acuta heterostropha algae eating invertebrate pulmonata shell fauna pest life aquatic plant fontinalis gastropods small animal standing water crawling nature wildlife invader south ukraine leaf floating plant