Binding of Isaac: Rebirth Wiki

Guppy's Tail is a passive item.


  • Grants a 1/3 chance of replacing Room Clear Awards with a Chest Chest or a Locked Chest Locked Chest, but also a 2/9 chance to replace it with nothing at all.
  • This item belongs to the Guppy set. Collecting three items from this set will transform Isaac into Guppy.


  • The drawback to this item is that Keys become much more scarce, while increasing the amount of Locked Chests. This makes taking Guppy's Tail a potential liability early on.
  • Due to any found Chests containing items while in Chest Chest or Dark Room Dark Room, Guppy's Tail can be a good way to quickly stack up more upgrades before facing the final boss.
  • This item has no effect in Greed Mode other than counting towards the Guppy Transformation.


  • Added in RepentanceGuppy's Eye Guppy's Eye: Makes Key Key management easier by revealing which Locked Chests are worth opening and which are not.
  • The Left Hand The Left Hand: Turns all chests into Red Chest Red Chests, allowing Isaac to get Red Chest items much more quickly. Useful when pursuing the Guppy Guppy transformation.
  • Mom's Key Mom's Key: Increases the number of drops from Chests and counteracts the increased chance to run into Locked Chests.

In-game Footage[]


  • This item is used in Cat Got Your Tongue (challenge #8).
  • The item Dead Cat Dead Cat has Guppy's tail be completely black while Guppy's Tail has a white fur on the tip of the tail.