I originally got this in a labeled Aquafleur pot, so I know this is the version of the fern I have.
In my four foot 75G tank I have two plants, each reaching out and touching every wall of the tank except the furtherest side-wall, though in one case it was only my pruning that stopped that. It was only after about six months and following a drastic prune of other plants that let more light through that they suddenly got this big. I then had to prune them quite severely to stop them shading the tank. Shortly afterwards they changed leaf form completely and now look like Ceratopteris Thallictroides as pictured here
. In a way this change is good, because the new leaf shape lets far more light through and I don't have to prune as much - with the old shape I was contemplating only allowing each plant to have two large branches at a time. (I prune by cutting branches off at the base.) However I miss the beauty of the original leaf shape - I believe Siliquosa is the most beautiful form of watersprite - what can I do to get the old shape back?
Here's a landscaping idea for small tanks: I planted a small Siliquosa daughter plant in the centre of my 10G, one inch from the front, intending to move it later. I never got round to moving it, now the fronds plaster themselves against all the walls of the tank, creating a green lacy curtain/backdrop. I cut off any that rest against front-centre obscuring the view into the tank center. Once the plant is big, there is a clearing immediately above the root ball that encompasses the whole center of the tank, and I plant other plants so they grew up between the branches into this clearing. In effect the Siliquosa becomes a one-plant jungle with built-in clearing.
It seems odd to recommend planting a huge plant in front-centre of a small tank, but once it has got big all the foliage is actually as far as possible away from the roots. The latest frond to uncurl from the base has had the branch reach the side of the tank generating only one small leaf (about an inch from the sidewall) along the way.
I've only had this tank in this layout for a short time, so it's possible there may be shortcomings I'm yet to experience.