Salvinia Minima is one of around 12 recognized species of Salvinia. Originally from South/Central America and West indies, it has been found wild growing in a number of north american states and due to its’ invasive nature has been banned in some of them including Texas. It is related to Azolla, another floating plant Genus.
Salvinia Minima is also known as water spangles, water moss(?) and other various names but is actually a floating fern. It is often confused with S. Natans and/or S.Rotundifolia. One way of identifying it is to get a magnifying glass and look at the hairs on the leaves. Typically Salvinia leaf hairs are joined at the top into a kind of “egg-beater” shape including S.Molesta and S.Auriculata and look like this…..
Salvinia Minima however has free ends to its hairs thus………
The leaves are arranged in 3s along a short stalk. 2 of these appear as floating leaves with the hairs as above. The third is finely divided and submersed and gives the appearance of roots. The “roots” therefore are in fact a modified leaf and not true roots at all.
Propagation in aquarium is by division. The stalk will grow producing more leaves and it may have more than 20 floating leaves along it. At some point the stem will separate and will become 2 plants. You may speed this up by dividing plants manually splitting the stems. I would advise leaving at least 4 leaves on each plant if you try this.
Lighting should be medium at least and no CO2 is required. The addition of more intense lighting and CO2 may assist growth. A wide range of PH is tolerated from 5.0 – 8.5. In all S.Minima is an undemanding plant easily kept and grown in aquaria. It has even been known to tolerate salt to 7000 ppm.
Benefits of Salvinia include Nitrate reduction (it is a great Nitrate vacuum sucking it out of your water!) and provides shelter for fry, shade for a controlled section of your aquarium for any submersed plants or inhabitants that prefer a little less light, and as a source of grazing for Shrimp. Some bubble-nesters like Gouramis and Bettas may use the underneath of the plants as a base for their nests. Dried Salvinia have also been used as a food source for growing infusoria to feed fry. Salvinia is not however a great source of nutrition for higher aquatic creatures in comparison to protein-rich Duckweed for instance. In it’s natural habitat it will however out-compete duckweed proving to be dominant in most bodies of water.
Management of Salvinia is easy thanks to the size of the plants, especially when compared to the nightmare of trying to remove Duckweed on a permanent basis. Left to its own devices, Salvinia will cover your aquaria. There are several ways to manage this including regular removal (be careful of those shrimp and fry hiding in there though!) Perhaps easier would be to contain them within a plant ring or matain a free space letting them grow around it…..
These plant ring may be made from numerous materials including airline linked in a loop, but are not always as successful as a product designed specifically for this purpose. Airline in particular may be difficult to get to float 360 degrees around its perimeter due to its more flexible nature.
Salvinia species are a great addition to aquaria provided they are controlled. They have many benefits to the shrimp keeper, not least in helping to control nitrate.
They are best kept with a plant ring either within the ring to maintain a small area of them or using a ring to maintain a clear space for feeding and to encourage the gaseous exchange within your water.
Mark has Salvinia in his shop for sale Here
For UK aquarium keepers you may find some here as well as the plant rings pictured above which are shipped worldwide: