Something different: newly acquired, this U. reniformis is already putting out great growth for me It seems to do very well in a moist mix of sphagnum and perlite, and hopefully I'll see it spread through the whole net pot.
A lot of my plants probably could, but don't have the money to refurbish all my lighting. And in reality, the plants have more pigment than my camera shows. The leaf petioles are somewhat reddish purple, and the veins on the underside have faint red blushes.
I don't think Bob is referring just to pigment. The leaves on U. reniformis are normally erect whereas yours look a little etiolated. More light would help greatly. The 'net' pot isn't necessary, many grow the plant as an emerging aquatic. It's not that fussy.
I use the net pot to let the plant choose where it wants to grow. It provides a moisture gradient, so once the plant finds the point where it's really happy, it will grow there. As for the "etiolated" leaves, they are growing at an angle toward the light, as they grow at the edge of the shelf they hang by, so they're stretched more due to that reason.
Agree with fredg on his reasons to avoid netpot with U. reniformis. I use netpots for most of the epiphytic utrics even though leaves & rolons come through the sides but as fredg noted - U. reniformis isn't fussy. Another reason for me is that U. reniformis has swollen rolons instead of tubers. While leaves are easily chopped off, trying to repot a U. reniformis that has swollen rolons weaving in & out of a netpot would be a nightmare. Here's an example in a regular pot. Based on examples like this & the fact that reniformis tends to go to the bottom of any pot & send out leaves from there, I started to grow a plant in an undrained tub. I'll probably add more in tubs as I get around to repotting.