male of european bitterling and sunbleak, beautiful temperate adult fish watch attentively and hide in driftwood covered in algae

acheilognathinae adult algae amarus animal aqua aquarium aquatic attentively beautiful behaviour biotope bitterling bright careful clear coldwater covered cyprinid decorative design driftwood ecology endemic europe european fauna fish fishkeeping freshwater gravel grey gudgeon hide lake line litter local look male natural nature pond protection rhodeus river spawning sunbleak tank temperate timid topmouth underwater vulnerable watch water widespread wild wooden