Toro-nagashi in Fushimi, Japan: Toro-nagashi 灯籠流し is a Japanese traditional event (sending off the spirits of the dead on lanterns floated on the waters of a river or the sea). It's part of the Buddhist festival Bon.
OMG I thought he encased real goldfish in resin. He hand paints each fish layer by layer within the resin to get this effect. Riusuke Fukahori Paints Three-Dimensional Goldfish Embedded in Layers of Resin