What does it mean for the rich to play with deep-sea eels?

It means spending money games played by rich people.

Deep-sea eel, the game of the rich, is a network stalk that has recently emerged. It refers to the spending game played by the rich. Participants in this game show their strength and status by competing for wealth and luxury goods.

Rich people who participate in the game need to expose their most expensive toys or other luxuries and comment and compare with each other. This game was originally initiated by a top rich second generation in Shanghai, and gradually evolved into a social activity within the national rich circle.