In this section

Learn about different zones in the ocean.
Examine species as their bodies change to meet the demands of different environments at each stage of life.
Explore how body types evolved as conditions on Earth changed over time.


The world in which fishes live

So many habitats - streams, ponds, coral reefs, kelp forests, mudflats, sandy beaches, tide pools, the open ocean, deep sea and more.

Terrestrial environments are places on land. Because terrestrial bodies of water such as lakes, ponds, streams and rivers are often physically separated from one another, conditions vary greatly between bodies of water for complex reasons. Though many terrestrial water bodies are associated with freshwater, hypersaline environments occur too. Because they are shallow, terrestrial bodies of water exhibit great seasonal variability in factors such as temperature and oxygenation.

In contrast, marine environments are interconnected, deeper and more uniform. Even though it looks uniform on the surface, significantly different regions of the ocean exist too.

What are the Earth’s significantly different aquatic environments? Conditions in marine zones vary with respect to depth, sunlight and influence of land, among other things. No physical wall separates these zones, but certain kinds of fishes with certain characteristics tend to populate each zone. Learn about each zone and the fish that live there.

We'll start with marine zones and the kinds of fishes that prefer each zone, and then move on to terrestrial zones and fishes that migrate between both. We'll finish with examples of aquaculture - places people have made to raise farmed and ranched fishes.

Title - Environment, adaptation, behavior.

In this section, learn about:

  • How biologists divide the ocean into areas that are significantly different?
  • Important differences between terrestrial and marine environments
  • Key features of fishes that live in different habitats
  • Why more fishes live in coastal and reef environments
  • How humans are modifying habitats for wild and farmed fishes