What plant is this?

[Lily413]

Im sorry ive been asking so many questions, im a little in over my head. I have a 20 gallon and a 5 gallon tank. When i bought live plants a week or two ago the woman told us a few wrong names. I was able to id everything other than one plant. Any idea what this is? I noticed some of the leaves seem like theyre decaying. Any idea what could cause that? I havent added any supplements because the person i bought the plants from said they would be fine for a few weeks but im guessing thats wrong. I have this plant in both tanks. One has amazon sword with whatever this is. The 20 gallon has what i think is anubius and red cryptocoryne wendtii. I have them numbered in the photos. Can someone confirm if those are right?
1&3: mystery plant
2: amazon sword
4: anubius
5: red cryptocoryne wendtii
Here are the 5 plants

 

[Mudminnow]

I believe your mystery plant is Rotala rotundifolia.

I think you're generally correct about the rest. 2 looks like some kind of sword, 4 some kind of anubias, and 5 some kind of crypt.

 

[Static823]

number 3 kinda looks like elodea to me