Freshwater
Chara fragilis
Characeae
Characeae
Seen in the wild in Czechia, France, Germany, Poland, Sweden, and United States.
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.
Light, nutrients and CO₂ in balance, low tech versus high tech, and how to read from the leaves what your plants are missing.