A natural underground spring.
Loaches are freshwater fish, for example, the clown loach which is a freshwater fish.
fish and humans
Swamps and Marshes
There is much more saltwater than freshwater. All of the oceans are made up of saltwater for example.
I'm not aware that any exist. Phylum Echinodermata is often mentioned as the largest without freshwater or terrestrial representatives.
a salt marsh is a wetland that has fresh water
-( 0 0 )- -| |- -(____)- <<<<< this is an example of your crab!
pesticide runoff from farm fields
A mountain stream, or a river flowing lower down in the valley.
Pesticides run off from farm fields.
Well predation the preying of one animal on others. So an example would be herrons and fish
A freshwater ecosystem is where animals for freshwater and animals who swim or live by freshwater live. For example: animals such as crocodiles, freshwater fish, turtles, or frogs, live in a freshwater ecosystems. I just named some from North West Florida's main freshwater ecosystem.