The white version of the box has now been released in a set. It has been around for a few years though at the Funpark.
At the Fun Park in Germany is a game for visitors that are some large clams with water flowing in them. The water brings with it small items, and some of them are water related animals. This is the box you can purchase to hold the items in. Special thanks to Clare and Nick, and Disnoke for acquiring some of these for me.