by Robert Paul Hudson
Fontinalis is found throughout North America, Asia, and Europe. It is a true cold water plant, particularly in North America. There are several species in North America alone and two variations of Fontinalis antipyretica: the common variety and the gigantea variety. The “gigantea” has reached lengths of two meters, leaves 5-8 mm wide, and mats that cover an entire stream bed. The standard variety typically grows in fast moving streams while the gigantea version is more often found in quiet shallow pools. Typically its natural water habitat is low in pH between 4 and 5.5.
Excessive light and heat have the most dramatic effect on this plant. Studies have shown that 15 degrees C is optimum and after about five weeks of being exposed to 20 degrees C or higher it will turn from its beautiful dark green to a murky brown color and stop growing. This is when many hobbyists believe the plant is dead, but when the temperature drops back down it will usually turn back to the green color and begin growing again.
Willow moss is particularly sensitive to copper. First the tips of the branches show the signs of chlorosis at copper levels of only 3 ppm and then at 10 ppm, irreversible plasmolysis occurs and the cells are colorless. If you are trying to eradicate snails, do not use a copper based treatment with this plant in the tank.
The most practical uses for this plant in the aquarium would be for fish breeding, black water tanks, North American native species tanks, goldfish, paludariums with subdued lighting, freshwater shrimp tanks, or any aquariums with fairly low light levels and moderate temperatures.