Yeah, the Water Sprite plants vary in shape so much that you wouldn't think they were the same species from one to the next. It's a well known attributed of the plant. I have some with really big, wide leaves and others with tiny, fern-like leaves. Mind you, that happens on the same plant at times, too. Interesting plant to say the least.
Doesn't seem to be any rhyme or reason to the variations either. It's nice, though, 'cause you can get diff't textures without using more species of plants.
On the left: Freshwater Fern (yellowish plant, tan leaf tips)
"Blue" plant on the right: Lobelia (dark green leaves, slight purple tint to some leaf edges)
"Yellow sword-like plant": Red Rubin (rusty red with green highlights in leaves) --> assuming you were asking about the one in the back right corner of the photo
Thanks again for the comments! Hope I've covered the plant questions?