The only way I know the sex of mine is that Gypsy (the calico) shoves Blondie headfirst into the the pot of hygro (the pot behind them in this photo), which makes Gypsy male. (That's spawning behavior, and can get quite aggressive.)
My tank has all live plants in it. 5 anubias - tied off to rock (that's anubias you can see under their chins - the leaves are too tough to eat), the pot of giant hygro (it's a stem plant and I've got several stems in an unglazed terra cotta pot that they kept uprooting and dragging around the tank for a while), a potted retrospiralis crypt that melted but is putting on new leaves (it's to the right of them), a java fern mat, and several stems of floating anacharis and pennywort.
I think the floating stems distract them to some degree from the other plants (I can replenish those from my tropical tanks). The pots are 3" diameter pots and are really hard for them to get into, but you can see goldfish butts upended in them from time to time. I capped the pots off with gravel to give them some weight and make it harder for the fish to get into them.
I'm probably going to try a couple of jungle vals in the back of the tank. Those will go straight into the gravel. The java fern must not taste good, because except for trying to get hold of a corner of the mat and wag it around, they leave it alone.
I've got an album in my profile with a few full tank shots.