“almond leaf” for betta?

Hi! This question is for @dwalstad but if anyone else has input of course it is welcome.

At my LFS, the bettas are in little cups with a little leaf that makes the water yellow/brown. I asked about it and was told it is an “almond leaf” which is an antibacterial which is good for the fish but also good against algae because “algae is a bacteria”. I was like ok give me some of those leafs, haha… This is El Natural, after all.
But now of course I’m second-guessing and can’t find anything about “almond leaf” in The Book, I’m honestly a little confused about the difference between algaes and cyanobacteria and the helpful bacteria that I might have killed by introducing the leaf… the snails are not particularily interested in the leaf, which is noteworthy … and there aren’t very many questions in this post but please give me your thoughts.
I’ll post photos of the leaves in the next comment. It is important to note that there might be a language barrier and “almond leaf” might be something completely different. The LFS is Chinese, and we communicate in Spanish, and I’m writing here in English. The Chinese lady at the LFS usually gives me the scientific names of plants in broken Spanish and I can figure it out, but this time she just said almond leaf.