Where is this commentary sourced from? It's not present on the listed source, which looks to be the uploader's own tweet. Please try to source your uploads and commentary properly.
As for the picture itself, it seems like a photoshop. I've seen it floating around on posts from several accounts, but never from the actual zoo. The real memorial at the zoo can be seen here and here on their official account. Fururu's VA hasn't tweeted this picture either.