monkey goby (neogobius fluviatilis) juvenile freshwater fish, caught in southern bug river, in nature aquarium

adaptable america animal aqua aquarium aquatic biotope brackish bug caught clear closeup coloration cosmopolitan deathly decorative destructive ecology endemic european fauna fish fishkeeping freshwater goby gravel harmful highly invasive juvenile lips local masking mouth native natural nature north operculum predator proterorhinus rare river sand semilunaris southern squama tank temperate threat tubenose underwater unusual water weed widespread wild young