They like planted tanks, the female hangs the adhesive mass of wigglers among the Najas in my tanks. Being cichlids the adults may want to move things around to suit them though. That's one reason I like Najas, they can move it around and reshape it (and they do when they spawn) however they like without doing any harm to the plants.
I've never seen them eat any, unlike the cutteri. I tossed a big wad of Najas into the 55 when I move the cutteri juvies over for growout, and they ate all the leaves off of it. It's still green and alive, but it's just a mass of bare stems now.
The oblongum are great for controlling ramshorn or pond snails IME. They aren't as determined or agile as loaches, but they definitely keep them down to a minimum.