Pruning/maintenance help needed: ludwigia, anubia, ambulia
I'm still pretty new to all of this plant maintenance, have made it through a couple of algae outbreaks and am learning more every day. However, I feel like I missed the first day of some class when the basic instructions were passed out because I feel like I'm not sure where I am headed. I don't know how to take care of my plants now that they're doing well - this is one of the goals, right? - the place towards which we work, healthy plant maintenance.
So I have these plants that are growing (anubias, amulias, and ludwigia) and I think that I am supposed to be doing something to them, in the way of pruning, but I don't know what. Watching them, I have noticed that they don't look as healthy as they did before they grew out so much but the rest of the plants (more anubias, sags, glosso, micro swords) all look the same and very healthy. I've looked into pruning and then these plants in particular but I still feel as if I'm missing something. Any help or thoughts would be much appreciated.
The ludwigia grew like crazy up to the surface and started across it where it didn't look so nice. I read up on it and figured that I cut the stem and replant the top. This quickly doubled the size of the ludwigia forest but now I notice that some of the stems are soft, brown, and rotten. If fact, less than half, quite a few are like this and I don't know if it was a result of the trim or a water issue. There haven't been any changes to fert regimine or water quality that I know of.
The anubia's rhyzome is growing and now resembles a catepillar. The older end is less pretty and still has some healthy leaves but all new growth is from the other end. If I cut the rhyzome into two, will this kill the older half or will I have 2 anubias?
The ambulia is a new addition for me and in 2 weeks has shot right to the surface. I've read that I can cut it in half and replant the top but I'm not sure what this does to the bottom. Will the bottom half just rot away?