Hmmm... Normally it helps to give some info about your set up, like what kind of lights do you have? How big of a tank is it? What kind of substrate (if any?) are you using? That can affect the kind of plants I'd recommend for you.
As long as you have a fluorescent light of some sort over the tank (T8 or T12 is fine), I'd suggest trying plants that can live happily floating at the water's surface: anacharis, java moss, water wisteria, frog bit, and water sprite. I've had a lot of good luck with crystalwort (
Riccia fluitans), too, as long as it's floated at the top (versus being tied to other decor underwater)! Like someone else mentioned, you'll get the benefit of having live plants (using waste, adding O2), PLUS a little shade for your axys.
On the other hand, if you have a sand substrate and a tank that isn't too deep (under 25"), you could try some anubias species (keep rhizome above the substrate), valisneria (apparently--haven't tried these, myself), and java fern (again, rhizome above substrate). In these conditions, you could plant the anacharis. Tying the java moss to decor would work here, too.
Please note that if you have 1) a deeper tank 2) a big tank with a low-power light or 3) rock substrate/bare bottom, I'd probably try the floaters and skip anything in the second bunch. Go for silk plants on the bottom (if you want the "planted" look but can't support it) and live floaters on top!
If you don't have a fluorescent light, skip the live plants altogether. They may survive a while in your tank, but are ultimately just slowly breaking down and worsening your water quality...
Good luck!!
Jeni