Thanks Rob.
Yes, I have tried pennywort. I have a bit in there now. Its wrapped around a branch on the surface.
I'm hoping it will take. I had it planted in the substrate at first but It was not doing very well. Hopefully I will have more luck with it as a floating plant.
It's one of those easy to grow plants that I have trouble with.
I’ve had trouble growing it too. In large or small tanks. Not sure why.