Shadow Fish are underwater enemies found in the Beach Gate levels.
Once they notice The Hero, they will start swimming quickly towards them in order to attack them. Due to the underwater areas where they are encountered often being quite constrictive, they can be very difficult to avoid. However, if The Hero hides in Seaweed, the fish will not notice them, enabling The Hero to get past them much more easily. The Angler King produces Shadow Fish during the second part of its boss battle.
Shadow Fish resemble fish skeletons that are completely black and oozing with Shadow.
- The Shadow Fish that the Angler King produces take two hits to defeat, compared to the one hit that is required to defeat regular Shadow Fish.
- Shadow Fish swim faster when they chase The Hero.
- An enemy named Fish Bone in the Mario series bears a strong resemblance to Shadow Fish, as they are both skeletal fish who swim faster when chasing the protagonist.
- A Shadow Fish can not be defeated by jumping, and can only be killed by the starzooka.