That jack Dempsey and convict are going to out grow tank in a couple years. I personally have a 8-9in jack dempsey and a 5-6in convict. Once they get to be that big anything smaller, especially those danios, will be toast and you'll be left with the jack Dempsey and the convict. What I would recommend is to either get rid of the jack dempsey and the convict or you could get a bigger tank just for the cichlids and turn the 20gal into a planted community with the angels and smaller fish.
As for the planted part I would say go with 1-2 wpg anything more would start going into the high tech area(assuming you want to stay low tech because you posted in the low tech forum).
For the substrate what I like is a mix of sand and a flourite because it makes it easier to hold down large plants like swords.
For plants, I personally like amazon swords, crypts, and vals. They have worked out really well for me.
As for the planted part I would say go with 1-2 wpg anything more would start going into the high tech area(assuming you want to stay low tech because you posted in the low tech forum).
For the substrate what I like is a mix of sand and a flourite because it makes it easier to hold down large plants like swords.
For plants, I personally like amazon swords, crypts, and vals. They have worked out really well for me.