
The Angler's quotes about the quest fish can give players hints about the features and enemies of the biome they can be fished in if the player has not explored them yet.This works similar to the Encumbering Stone.
One quest fish can also be stored in the inventory's trash slot.
To collect more than one of a quest fish, the player must store each fish in a storage item as it is caught later they can be moved back to the inventory. However, they can be moved into the inventory from a storage item (shift-clicking and other "auto" features will not work). Quest fish are the only items that cannot be picked up if there is one already in the inventory. Only four fish can only be caught at Cavern levels or below: Demonic Hellfish, Fishotron, Guide Voodoo Fish, Hungerfish the other "Cavern" fish can also be caught at Underground levels as well. All "Underworld" fish can also be caught at Cavern levels. Only the Angelfish and Cloudfish must be caught in Space/Sky all other "Space/Sky" fish can also be caught on the surface.
Indeed, no quest fish has any use beyond the Angler's quests. Unlike the Bomb Fish, the Dynamite Fish does not function as a stick of Dynamite.