福寿螺为外来入侵物种,原产地为南美亚马孙河流域。成千上万的长得如同高尔夫球大小的福寿螺生活在稻田里，啃食稻田的根茎，这样“凶残”的物种简直是小蝌蚪的天敌！
Hundreds of thousands of snails that grow to the size of a golf ball are not only taking over and eating the Ebro delta rice fields but also threaten to destroy the delta ecosystem.

凤眼莲（水葫芦）作为外来入侵生物的代表，繁殖能力超强，国内很多水域都可见其子孙，屡屡酿成环境事件。小蝌蚪只能绕过凤眼莲继续自己的旅途。
Eichhornia crassipes (also called "water hyacinth"), originally from South America. Today, the damaging effects of the plant are well-known. Infestations of this weed block waterways, which in turn limits boat traffic, irrigation, drainage and aquatic breeding.

如果把巴西龟放生，因基本没有天敌且数量众多，将严重威胁我国本土野生龟与类似物种的生存。聪明的小蝌蚪没有理会红耳龟的搭讪，继续他的旅途。
The red-eared slider is a turtle that has been listed among the world's 100 worst invasive alien species, as identified by IUCN. The species proved to be a medium to spread disease and has caused great destruction in turtle populations in China.

小龙虾是存活于淡水中一种像龙虾的甲壳类动物，学名克氏原螯虾，他是甲壳类中分布最广的外来入侵物种。就在这危机的时刻，青蛙妈妈出现了……
The signal crayfish, Pacifastacus leniusculus, is a North American species of crayfish. It was introduced to Europe in the 1960s to supplement the Scandinavian Astacus astacus fisheries, which were being damaged by crayfish plague, but the imports turned out to be a carrier of that disease. The signal crayfish is now an invasive species.