[quote=”Jacob” post=4743]What about pistia, water lettuce? It has leaves in the air and no need to root in the substrate.
How does it compare to submerged water sprite for keeping the water clean?
And is it a plant that could alter the water chemistry too much like “normal” plants will?[/quote]
I have loads of Pistia stratiodes. I’m actually thinking of getting rid of all of it, because it seems to look pretty for a while and then eventually either make a big mess or take over a tank.
It is also extremely iron-hungry. I have to fertilize the tanks it grows in fairly often or they become chlorotic and die (not parosphromenus tanks), and rob the other plants of iron in the process. As Zwerge said, Salvinia works very well. I have so much salvinia now that I have given fistfuls of it away to other hobbyists and even people who have small fountains and ponds outside their homes. I have never had a problem growing salvinia, and while it does respond to fertilization (as one would expect), mine does very well without it.
I have also had great success with frogbit; it seems to take some time to get used to the lower pH, but after that it just goes right back to making glossy, round leaves.
As for the topic at hand, the tank photo that started this thread certainly looks nice (and Finke is absolutely right about aquariums here in the US; people always seem to want to engineer problems away instead of looking to the inspiration of why we have glass boxes of fish in the first place; natural ecosystems.
And, the natural ecosystem for southeast asian blackwater fish is very acidic, with very low concentrations of important plant micronutrients such as magnesium, potassium, iron, and calcium. In order to correctly mimic the ecotope of Parosphromenus in captivity, we need to keep the levels of these micronutrients low, and because of that many plants simply will not survive in a proper Parosphromenus tank.
The tank in the photo at the start of this thread looks nice, but it’s probably not going to be the best for Parosphromenus.