I would go for the mix...the fish would fill up the water column..
it is blyxa but by the root will be filled with blyxa and some in between the 2 wood on the left side near the main stump also... it just needs to grow in and it should fit in with where the rocks are locatedsomething about those rocks that aren't doing it for me. too scattered I think. They might look better bunched up in that opening among the roots where the blyxa (or is that stargrass) is