Hello all, here is an update on our aquarium and a question. What types of plants are recommended for freshwater aquarium and why? I know in general that they help filter the nitrogen and other things in the water, but are there specific ones that are better than others? I had just a few plants from the local pet store initially, and need to replace a couple that didn't do so well over time. 
Here's the general view, as you can see, only a couple small plants left.
We have 6 large goldfish, 2 Plecos (which are getting big!) and 3 little glowfish, I don't know their real name.
Here are the two Plecos, these must be 10 inches long now.