juvenile european perch frightened and curious in dense vegetation of potamogeton water plants on sand bottom of coldwater river b

adaptable animal aqua aquaculture aquadesign aquarium aquascape aquatic attack attentive background beast behaviour biotic biotope body bottom clear coldwater colourful cosmopolitan curious dangerous dark dense design dominant ecology enduring eurasian european fauna fin fish fishkeeping fluviatilis free frightened gravel greedy green ichthyology insatiable juvenile looking macro natural nature orange perca perch plants postcard potamogeton predator protection ready river sand space stripe substrate swim system tank ultimate underwater vegetation vulnerable water weed widespread wild