Fishing potion
From Emps-World Wiki
When drinking a Fishing potion your Fishing level will be temporarily increased by 6. The boost will gradually wear out and your fishing level will return to its original level. With fishing potions you will be able to catch fish for which you normally do not have the required fishing level. They also increase the speed of catching fish.
Fishing potions can be made by combining Snape grass and an Avantoe potion (unf). This requires a Herblore level of 56 and will grant 565 experience.