The invasion of non-indigenous plants, animals and fungi is one of the most serious worldwide problems. It will be the main issue of the protection of biodiversity in the 21st century. That is why the international convention on the protection of biodiversity provided the need to control non-indigenous invasive species posing a threat to native habitats, communities or species. Due to this, the definitions of invasive and non-invasive species must be defined, the scope and form of human impact in regions valuable in terms of their natural values and under strict legal protection must be established; aquatic ecosystems should be put under special protection.