E. bleheri is a very common sword species and doesn't require too much in the way of lighting. It's also tough. Unfortunately, it's not tough enough for an oscar. I don't think any plant is. Even if the oscar didn't tear them apart, he would constantly be uprooting them with his digging habits. I've kept oscars before, and the simple truth is that no live plants will endure them for long. Well, floating plants would, but nothing rooted.
hey, if it doesn't work out I can always move the oscar. No big deal.
Here's a list I've been generating of "maybe" plants to keep. I wouldn't keep all of these.
Anubias Lanceolata
Java fern
Java moss
Anubias Afzelli
Aponogeton Crispus
Cabomba (Carolina)
Moneywort
Pennywort (Hydrocotyle leucocephala
Baby Tears Micranthemum Umbrosum
Cryptocoryne Beckettii
Cryptocoryne Wendtii
Cryptocoryne Wendtii De Witt
Saggitaria Broad Leaf (platyphylla)
Echinodorus Horemanii (Green)
Green Ozelot Sword(Ech. Ozelot)
Bolbitus (Fern) (Heudelotti) (Medium green fronds)
Moss Balls (Chladophora Aegagropila)
Limnophilia aromatica
Gymnocoronis Spilanthoides (New!) (South America)
Riccia Fluitans
Pennywort (Hydrocotyle leucocephala)
Giant Hygro (Hygrophila corymbosa)
Micro Sword (Lilaeopsis nova-zelandiae)
Pygmy Chain Sword (Echinodorus tenellus)
Giant Hairgrass (Eleocharis montevidensis)
Cryptocoryne walkeri (lutea)