@ cs_gardener: yes, Ludwigia on the lest needs some pruning, and I'll do that as soon as the stems get just a bit more stronger. Also, R. rotundifolia in front of if was cut just a day before taking this pic, so this plant also needs to fill it's space.
@ stepheus: you are absolutely right: as I said, java fern was taken from a 75 litres tank which became too small for this plant. So, if looked at closely one could see that the plant shows a cube-like shape, something like square shaped watermelons in Japan.

)) In the midground I planted some brown leafed Cryptocorynes - they are visible on the second picture. It will take some time for them to grow and become more visible, I hope.
@ Nevermore: well... this Microsorium and I go a long way and I just couldn't disregard it's need for space. Also, stargrass REALLY grows too fast and I don't have the time to maintain it in presentable condition. Moreover it used to spread across the surface shading the rest of the plants, so a compromise had to be found. Stargrass now (one part of it) grows in 75 litres.
Thank you all for the imput. stepheus, all comments are welcome - two heads are always smarter than one!
