
Freshwater
Potamogeton filiformis
Potamogetonaceae

Potamogetonaceae
Lives wild in Afghanistan, Argentina, Austria, Baltic States, Bolivia, Canada, Chile, China, and 39 more countries.
Soft, acidic water, subdued light, sand, roots and fallen leaves: how to set up a biotope aquarium from the Amazon and the rivers around it.
Two aquariums from Southeast Asia: calm forest streams and peat swamps with soft, brown water, and fast mountain streams with cool, oxygen-rich water.
Streams and ponds in North America are often cool. How to set up an aquarium without a heater, with pygmy sunfish, shiners and darters.
A coldwater aquarium with European fish and plants, without a heater. The water follows the seasons, and summer heat is the biggest problem.