That looks real nice! perfect for some rainbows with all that length!
Try using Ludwigia repens for a splash of red in there too!
Any reason the water level is that low or were you doing a WC?
In a species / tetra tank they will feed from the top but otherwise they eat food from the middle region as mentioned...
slowly sinking foods like JBL discus and colourbits go down well.
L128 is around the $180 mark.
they get bluer in highly oxygenated water.
i have posted links to my L128 earlier in this thread so you can see what they look like.
same with L66 - link included as well.