You should also look at Azolla. It grows crazy fast and is also high protein and fixes both carbon and nitrogen.

https://en.wikipedia.org/wiki/Azolla

Thanks, I'll see if I can find some.

I'm currently also experimenting with duckweed growing in my backyard, although I find that it doesn't play well with the other aquatic animals and plants, as it appears to smother them out.

If you have problems with duckweed smothering, azolla will probably be worse. Duckweed has to pull nitrogen from the water, azolla harvests it directly from the air. It makes a good feedstock and fertilizer though.

Here's the question: how does it taste?

Fresh, it's pretty tasteless, and quite easy to incorporate raw into other foods such as a smoothy, soup, pesto, or a spread in sandwiches.