aggressive eurasian ruffe, captive dominant wild freshwater fish, omnivore coldwater species, hornwort and elodea

gymnocephalus cernua perciformes percidae pope predator biotope adult gray driftwood eurasian europe ukraine litter adaptable water clear aqua animal beast aquatic fishkeeping hobby underwater decorative fish tank macro fauna widespread ecology threat ecosystem nature protection controlled conditions wild caught environment dark pet shop dangerous behaviour ichthyology weed space rare local deathly shallow dof wildlife interaction glass refraction blurred background aggressive ruffe captive dominant freshwater omnivore coldwater species hornwort elodea rich vegetation european river aquarium relaxing aquadesign led low light