Concept:Aquatic Animals live in water for most or all of its life.It may breathe air or extract its oxygen from that dissolved in water through specialized organs called gills, or directly through its skin.Aquatic animals are those animals that live in water are called aquatic habitats. Ponds, swamps, lakes, rivers, and oceans are some examples of aquatic habitats.Explanation:All animals given in the option except crow is an aquatic animal.While crow is a bird from the Corvus genus.Fish, Tortoise, Crocodile, Duck (aquatic bird) are an example of aquatic animals.Hence, from the above-mentioned points, it becomes clear that Crow is different from the others.