You haven't mentioned the tank size, but if this is the 20 gallon mentioned in other threads (or a 10g), then yes, this plant is too large. I had a Red Tiger Lotus (Nymphae lotus) in my 90 gallon tank, three actually because it somehow divided (can't remember how, it was several years ago I noticed the new plants arising from the substrate). I encouraged the floating leaves because that was the effect I wanted, large red floating leaves, and the one plant covered most of the surface and I cut off leaves periodically. I have never tried to grow this is shallower tanks (the 90g was 24 inches/60 cm high) but I can envisage a real tangled mass of stems.