Fish

Freshwater fish are fish that live in rivers, lakes, streams, and ponds instead of the salty ocean. They come in many shapes, colors, and sizes. Some are tiny, while others—like catfish and sturgeon—can grow very big! Freshwater fish breathe through gills, which take oxygen from the water, and most have scales covering their bodies. Many of them are important for people too—we eat some, keep others as pets in aquariums, and watch them in the wild.

Saltwater fish live in the oceans and seas, where the water is salty. They come in thousands of different kinds—from tiny colorful clownfish to huge sharks and tuna. Some live near coral reefs, some deep in the dark ocean, and others in the open sea. Saltwater fish have special bodies that help them survive in salty water. Many are bright and colorful, while others are built for speed, strength, or camouflage.

Deep-sea fish live far down in the ocean, where it’s dark, cold, and very deep. Sunlight can’t reach these parts of the sea, so many deep-sea fish look very different from the ones we know near the surface. Some have big eyes to see better, sharp teeth, or even bodies that glow in the dark! Because food is hard to find so deep down, many of these fish are great at waiting, sneaking, or surprising prey. They are some of the strangest and most amazing creatures on Earth!