Freshwater

From WikiAquarium

Freshwater is water that comes from lakes, rivers, streams, etc. and does not contain salt unlike the ocean or saltwater. A freshwater aquarium refers to an aquarium which contains plants and/or fish and water that does not contain much if any salt.

Many aquarists have freshwater tanks because they are a bit easier to maintain. If you are a beginner it is sometimes advisable to start with a freshwater aquarium because there is less work to do.