Cosmic fish is a valuable catch in the Harvest Moon game. This fish can be found in the river during rainy weather and at night. If you manage to reel in a Cosmic heart fish, you can sell it for a good price. In addition to its worth, it is also highly sought after by fishermen for its ornate beauty. So, grab your angler gear and head to the creek side to try your luck at hooking this Cosmic heart fish. Happy fishing!