Furfish

Furfish is a special fish used in potion crafting. It is obtained by fishing on the surface of any Forest Biome, making it a biome-specific catch rather than a general fishing drop.

Because Furfish is tied to surface fishing, it is most relevant once a player is looking to stock up on crafting ingredients rather than just food or sale items. Its main value comes from being kept for potion recipes, so it is worth setting aside any Furfish you catch instead of treating it like ordinary fish.