Highlight and describe in detail the key features of an aquatic animal

The have gills instead of lungs, which help them breathe underwater. They are cold-blooded, which means they can adapt to cold weather, such as the water. They have fins which helps them swim easily through the water.
Hope this helps :)

An aquatic animal is an animal,
either vertebrate or invertebrate, which lives in water for most or all of its life. It may breathe air or extract its oxygen from that dissolved in water through specialised organs called gills , or directly through its skin. natural environment and the animals that live in them can be categorized as aquatic (water) or terrestrial (land).