Cosmic heart fish is a valuable catch in the Stardew Valley game. This heart fish can be found in the creek during rainy days and at night. If you manage to catch a Stardew eel, you can sell it for a decent sum of money. In addition to its price, it is also in demand by anglers for its exquisite appearance. So, grab your tackle box and head to the streamside to try your luck at capturing this Cosmic heart fish. Happy fishing!