well, light, flow, nitrates, and open space are all stress causing.
choking the entire surface up with a labrynth of hyacynth provides shade (enabling light to be on promoting photosynthesis, promoting cleaning and carbon removal) and the roots diffuse flow (which i had little of anyway)
the axolotls took to it well, they spend half their respective time exploring in the roots and between plants.
the plants are connected by running stems, the axies seem to like sitting on these. even exposing themselves to direct light, it doesn't seem to stress them if there is shade and refuge immediately available. So all in all it seems to promote healthy activity and makes them more fun to watch.
also the plants are teeming with midge larvae, and the axies have been hunting them, they are tiny and hardly a snack, but they are activity,
im going to introduce some milfoil, damselfly larvae and freshwater shrimp from local lakes.
the milfoil brings planara to consume food waste, the damselflies consume fly larvae and become good food for axies, and the shrimp are the primary food supply for our local populations of neotenic tiger sals... figure they would be good for axies too.