For w5996, I found out that the mermaid in question is [[人魚(よもやま四方山)]]. Be careful when adding tags and, in my opinion, you should try finding sources that are unfamiliar to you before adding them as tags.
Honestly I was just copy-pasting the sources in the Google Sheets materials list, I don't know what a handful of them mean *exactly*. Of the ones that I do, I already categorized them.
Actually I didn't categorize this one. I noticed it but left it alone since I wasn't sure what the materials list meant by it; someone else categorized it.
Isn't this tag a little too generic and vague? Additionally, I am not sure if it should be parented to "animals" since mermaids are fictional creatures.