Growing salvinia is a bit of a problem for us in ponds and you should understand a few things before you use this plant.
In warmer areas, salvinia or water fern can become a serious invasive plant if ever allowed to escape into natural water sources. This plant comes with a class A invasive-plant alert.
Still Or Barely Moving Water
The plant floats on still or barely moving water and will quickly grow to cover the entire pond area (or as much of it as you’ll let it). This will shade out any submerged oxygenators you’re growing and it will slow down oxygen exchange.
Slowing down oxygen exchange means your fish will have problems. Either than or you’ll have to increase the water flow to compensate for this plant’s rapacious growth.
May Not Survive Winter
If your climate freezes solid, this plant will not survive the winter (or it’s not supposed to). Young plants produce small fronds and look like small floating ferns. This is why the plant is often sold. Mature plants form mats on the surface of the water and interlace their fronds forming impenetrable mats.
This plant grows as quickly as any other of the surface covering plants but it isn’t (in my opinion) as attractive as water lettuce or water hyacinth.
Drop a bit in a pond in full sun. It will grow.
But I wouldn’t grow it and I live in a cold USDA zone 4. Enough said.