The device known as shoyu-tai (or soy-sauce snapper in Japanese) was invented in 1954 by Teruo Watanabe, the founder of Osaka-based company Asahi Sogyo, according to a report from Japan’s Radio Kansai.
It was then common for glass and ceramic containers to be used but the advent of cheap industrial plastics allowed the creation of a small polyethylene container in the shape of a fish, officially named the “Lunch Charm”.
The invention quickly spread around Japan and eventually worldwide, and it is estimated that billions have been produced.
PLA is pretty brittle AFAIK. these need to be squeezed, so i’m not sure it’d do… perhaps they could add something to it? but whether that additive would also be compostable… it’d certainly make it non-recyclable
I used to buy the olive oil containers for a restaurant I owned. They worked quite well. Small single serving cups with a peel off lid. I don’t know if the lids were bioplastic, though.